Title of Invention	APPARATUS AND METHOD FOR NEIGHBOR ASSISTED COMBINING FOR MULTICUST SERVICES
Abstract	A method and apparatus for neighbor assisted combining for localized multicast services. User equipment (120) is sent a signal (730) indicating the relationship between cells with respect to serving cells (112) transmitting a common multicast transmission. At least a portion of the common multicast transmission is transmitted (740) on the same resource on each serving cell. A pilot signal is transmitted (750) on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell. An interfering signal and a related pilot are transmitted (760) on at least one different cell (114) from the serving cells.

Title of Invention

APPARATUS AND METHOD FOR NEIGHBOR ASSISTED COMBINING FOR MULTICUST SERVICES

Abstract

A method and apparatus for neighbor assisted combining for localized multicast services. User equipment (120) is sent a signal (730) indicating the relationship between cells with respect to serving cells (112) transmitting a common multicast transmission. At least a portion of the common multicast transmission is transmitted (740) on the same resource on each serving cell. A pilot signal is transmitted (750) on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell. An interfering signal and a related pilot are transmitted (760) on at least one different cell (114) from the serving cells.

Full Text	APPARATUS AND METHOD FOR NEIGHBOR ASSISTED COMBINING FOR MULTICAST SERVICES BACKGROUND 1. Technical Field The present disclosure is directed to a method and apparatus for neighbor assisted combining for localized multicast services. More particularly, the present disclosure is directed to using at least one serving cell and at least one extended serving cell for broadcast and multicast services. 2. Description of Related Art Presently, to deliver a multicast/broadcast stream in the Radio Access network (RAN) efficiently, two possible methods can be used. One is simulcast and the other is localized multicast. In simulcast mode, a Multimedia Broadcast Multicast Service (MBMS) service area is identical to the RAN system coverage area. All the cells broadcast the same data using the same physical layer resources (denoted "resource elements" or "resources" for short). A resource element is a unit of physical layer resource into which data can be multiplexed. A resource element can be one of, a multiplicity of, or a combination of, a time slot, an orthogonal spreading function such as a Walsh code, a subcarrier (such as is used in Orthogonal Frequency Division Multiplexing, or "OFDM"), or the like. Since identical transmissions from multiple cells on the same resource can combine such that they appear as a single transmission, in systems such as an OFDM based Enhanced MBMS (EMBMS), this could reduce the inter-cell interference if the allocated resource element is identical, which can improve transmission efficiency as measured in Bits/Hz. For a service with a very large number of users and when the service is widely distributed in the RAN, simulcast can be a very efficient transmission technique. For example, simulcast can be useful for transmission of weather reports, music, movies, etc. Simulcast is not efficient if the service area is much smaller than the system coverage area. For example, if the service is mostly focused in selected multiple cells, such as for clip replay for football stadiums, sport centers, local weather reports, or the like, it is not good to turn on all the cells in the system to deliver the localized service to just the selected cells. Most of these MBMS services may fall into this category of localized MBMS. In other words, simulcast is not an efficient way to improve efficiency as measured in Bits/Hz/km2. For the localized MBMS service, counting can be used to determine the user status of the cells, such as to determine which cells contain users who desire the service. Then an efficient radio bearer will be established in the appropriate cells to deliver the MBMS service. Unfortunately, during a localized multicast session, neighboring cells interfere with the localized service area cells. For example, neighbor cells may transmit on the same resource element as the serving cells, which will interfere with the common multicast transmission. Thus, there is a need for a method and apparatus for neighbor assisted combining for localized multicast services. SUMMARY A method and apparatus for neighbor assisted combining for localized multicast services. User equipment is sent a signal indicating the relationship between cells with respect to serving cells transmitting a common multicast transmission. At least a portion of the common multicast transmission is transmitted on the same resource on each serving cell. A pilot signal is transmitted on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell. An interfering signal and a related pilot are transmitted on at least one different cell from the serving cells. BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present disclosure will be described with reference to the following figures, wherein like numerals designate like elements, and wherein: Fig. 1 is an exemplary block diagram of a system according to one embodiment; Fig. 2 is an exemplary block diagram of a wireless communication device according to one embodiment; Fig. 3 is an exemplary block diagram of a controller according to one embodiment; Fig. 4 is an exemplary flowchart illustrating the operation of a network controller according to one embodiment; Fig. 5 is an exemplary flowchart illustrating the operation of a wireless communication device according to one embodiment; Fig. 6 is an exemplary illustration of a system according to another embodiment; Fig. 7 is an exemplary flowchart illustrating the operation of a network controller according to another embodiment; and Fig. 8 is an exemplary flowchart illustrating the operation of a wireless communication device according to another embodiment. DETAILED DESCRIPTION Fig. 1 is an exemplary block diagram of a system 100 according to one embodiment. The system 100 can include a network controller 140, a network 110, and at least one terminal 120. The terminal 120 may be a wireless communication device, such as a wireless telephone, a cellular telephone, a personal digital assistant, a pager, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a network including wireless network. The network can include base stations with cells (such as transmitters that serve part or all of an area covered by a base station) 112, 114, and 116. These cells can include serving cells 112 and extended serving cells 114. In the exemplary embodiment, one cell per base station is assumed. However, multiple cells may be present per base station. In an exemplary embodiment, the network controller 140 is connected to the network 110. The controller 140 may be located at a base station, at a radio network controller, at a multicast transmission server, anywhere else on the network 110, and/or may be distributed throughout various resources on the network 110. The network 110 may include any type of network that is capable of sending and receiving signals, such as wireless signals. For example, the network 110 may include a wireless telecommunications network, a cellular telephone network, a satellite communications network, and other like communications systems. Furthermore, the network 110 may include more than one network and may include a plurality of different types of networks. Thus, the network 110 may include a plurality of data networks, a plurality of telecommunications networks, a combination of data and telecommunications networks and other like communication systems capable of sending and receiving communication signals. In operation, the controller 140 can determine cells 112 in which user equipment, such as terminals 120, reside that desire a common multicast service. A terminal resides in a cell if that cell can be received better than other cells. For example due to variability in radio propagation, the terminal is not necessarily closer to the base station containing the cell than to other base stations. The controller 140 can select at least one serving cell 112 for transmitting the common multicast service where the selection can be based on the determination. The controller 140 can select at least one extended serving cell 114 from at least one serving cell neighbor cell which does not have user equipment that desires the common multicast service, the extended serving cell 114 influencing transmissions on the serving cell 112. The controller 140 can transmit the common multicast service on the selected at least one serving cell 112. According to a related embodiment, the controller 140 can signal to user equipment, such as terminals 120, a signal indicating the relationship between cells with respect to the serving cells 112 transmitting a common multicast transmission. The controller can transmit at least a portion of the common multicast transmission on the same resource on each serving cell 112. The controller 140 can transmit a pilot signal on each serving cell 112, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell 112. The controller 140 can transmit an interfering signal and a related pilot on at least one different cell 114 from the serving cells 112. For example, in a Multimedia Broadcast Multicast Service (MBMS), when one MBMS session begins, the controller 140 can perform counting to determine the user status of all the cells under the controller 140. If one cell has enough users, such as terminals 120, the cell can be a serving cell 112 and a broadcast mode can be established for the serving cell 112. The threshold for enough users may be a single user. If there are no users in a cell, such as in cells 114 and 116, the cell may not broadcast the data. A user, such as a terminal 112, can read Multicast Control Channel (MCCH) messages to determine if and how to combine a neighbor cell's 114 stream with its serving cell's 112 stream in order to obtain the diversity gain and/or the power gain. To elaborate, in Enhanced MBMS (EMBMS), interference may only come from other cells. This can be a major bottleneck for system capacity. If the controller 140 can control the neighboring cells with largest average interference to broadcast the same data using the same resource element or at least not use that resource element for other data transmissions, the interference level can be greatly reduced. This can significantly increase the system capacity. Counting can be performed when the session begins. Each cell can report its user status to the controller 140. These serving cells 112 form the service area. The controller 140 can then choose appropriate cells aside from the serving cells 112 that are the candidates for the strongest interference for the cells in the serving area. This cells form extended serving cells 114 in an extended serving area. The controller 140 can then control the extended serving cells 114 in the extended serving area to either broadcast the same data as the serving cells 112 in the serving area, in the case that cell power is available in an extended serving cell 114, or block the resource element that is used by an extended serving cell 114 in the case that cell power is unavailable at the extended serving cell 114. If the service area changes, such as by a user moving between cells, by a late joining user, or the like, during the session transmission, the controller 140 can adjust the extended serving area accordingly. Fig. 2 is an exemplary block diagram of a wireless communication device 200, such as the terminal 120, according to one embodiment. The wireless communication device 200 can include a housing 210, a controller 220 coupled to the housing 210, audio input and output circuitry 230 coupled to the housing 210, a display 240 coupled to the housing 210, a transceiver 250 coupled to the housing 210, a user interface 260 coupled to the housing 210, a memory 270 coupled to the housing 210, and at least one antenna 280 coupled to the housing 210 and the transceiver 250. At least one other antenna 282 may be coupled to the transceiver 250 to create an antenna array. The wireless communication device 200 can also include a multicast control information module 290, a receiver characteristic adjustment module 292, and a multicast transmission decoder 294. The multicast control information module 290, the receiver characteristic adjustment module 292, and the multicast transmission decoder 294 can be coupled to the controller 220, can reside within the controller 220, can reside within the memory 270, can be autonomous modules, can be software, can be hardware, or can be in any other format useful for a module on a wireless communication device 200. The display 240 can be a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display, or any other means for displaying information. The transceiver 250 may include a transmitter and/or a receiver. The audio input and output circuitry 230 can include a microphone, a speaker, a transducer, or any other audio input and output circuitry. The user interface 260 can include a keypad, buttons, a touch pad, a joystick, an additional display, or any other device useful for providing an interface between a user and an electronic device. The memory 270 may include a random access memory, a read only memory, an optical memory, a subscriber identity module memory, or any other memory that can be coupled to a wireless communication device. In operation, the controller 220 can control the operations of the wireless communication device 200. The multicast control information module 290 can receive control information needed for reception of a local multicast service on a serving cell. This information can include information common to multiple serving or extended serving cells, such as a notification that a service transmission will begin, how the local multicast service is configured in the air interface, and other information. The transceiver 250 can receive information regarding at least one extended serving cell, the extended serving cell being a cell where no wireless communication device desiring the local multicast service resides. The receiver characteristic adjustment module 292 can adjust at least one receiver characteristic of the wireless communication device transceiver 250 based on the information regarding the at least one extended serving cell. For example, the receiver characteristic adjustment module 294 can adjust at least one receiver characteristic based on the extended serving cell blocking a resource element related to transmission of the local multicast service on the serving cell. The receiver characteristic adjustment module 292 can also adjust at least one receiver characteristic by applying antenna adaptive algorithm weights for combining multiple antenna signals from the antennas 280 and 282. In operation according to a related embodiment, the receiver in the transceiver 250 can receive information regarding serving cells that are transmitting a common multicast transmission. The receiver can also receive the common multicast transmission, at least a portion of which is transmitted on the same resource on multiple serving cells. The receiver can additionally receive a common broadcast pilot signal related to the common multicast transmission, the common broadcast pilot signal being common to multiple cells. The multicast transmission decoder 294 can decode the common multicast transmission. The receiver characteristic adjustment module 292 can adapt characteristics of the receiver in response to receiving the information regarding the serving cells. The antennas 280 and 282 can comprise an antenna array. The receiver characteristic adjustment module 292 can adapt the antenna array in response to receiving the information regarding the serving cells. A user interface can present the common multicast transmission to a user of the wireless device 200. For example, the common multicast transmission can be presented via the display 240, the audio input and output 230 and/or the user interface 260. Fig. 3 is an exemplary block diagram of a controller 300, such as the network controller 140, according to one embodiment. The controller 300 can include a housing 310, a processor 320 coupled to the housing 310, a network connection 350 coupled to the processor 320, media content storage 360 coupled to the processor 320, and a memory 370 coupled to the processor 320. The media content storage 360 may be autonomous or may be located in the memory 370. The controller 300 can also include a counting module 390, a serving cell selection module 392, an extended serving cell selection module 394, a serving cell signaling module 396, and a transmission characteristic adjustment module 398. The counting module 390, the serving cell selection module 392, the extended serving cell selection module 394, the serving cell signaling module 396, and the transmission characteristic adjustment module 398 can reside within the controller 320, can reside within the memory 370, can be autonomous modules, can be software, can be hardware, or can be in any other format useful for a module on a controller. Also, each element of the controller 300 may be located at the network controller 140 or may be distributed throughout the network 110. For example, the media content 360 may be located at a media content provider, other elements may be located at different network controllers, and other elements may be located at different base stations on the network 110. In operation, the processor 320 can control the operations of the controller 300. The counting module 390 can determine cells in which user equipment resides that desire a common multicast service. The serving cell selection module 392 can select at least one serving cell for transmitting the common multicast service, where the selection is based on the determination. The extended serving cell selection module 394 can select at least one extended serving cell from at least one serving cell neighbor cell which where no user equipment resides that desires the common multicast service, the extended serving cell influencing transmissions on the serving cell. The extended serving cell selection module 394 can also select the at least one extended serving cell based on the at least one extended serving cell having a large average interference with the serving cell. The network connection 350 can send the common multicast service for transmission on the selected at least one serving cell. The transmission characteristic adjustment module 398 can adjust transmission characteristics on the extended serving cell to influence the transmission of the common multicast service on the selected at least one serving cell. For example, the transmission characteristic adjustment module 398 can adjust the transmission characteristics to transmit the common multicast service on the extended serving cell to influence the transmission of the common multicast service on the selected at least one serving cell. As another example, the transmission characteristic adjustment module 398 can also block transmission on a resource of the extended serving cell, where transmitting on the resource would influence the transmission of the common multicast service on the selected at least one serving cell. The processor 320 can indicate, via the network connection 350, to user equipment on the selected at least one serving cell that there is an unused resource on at least one neighbor cell. The processor 320 can also indicate, via the network connection 350, to the user equipment on the selected at least one serving cell, the resource element used on the serving cell and which extended serving cells block the same resource. The user equipment can then adjust receiver characteristics and/or antenna characteristics more efficiently based on the knowledge of transmission characteristics of the neighbor cells. The processor 320 can detect a need to change the service area including adding or removing a serving cell and the extended serving cell selection module 394 can adjust an extended service area including adding or removing an extended serving cell based on the processor 320 detecting the change. In operation according to a related embodiment, the serving cell signaling module 396 can signal to user equipment a signal indicating the relationship between cells with respect to serving cells transmitting a common multicast transmission. The network connection 350 can send a signal for transmitting at least a portion of the common multicast transmission on the same resource on each serving cell. The network connection 350 sends a signal for transmitting a pilot signal on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell, The network connection 350 can send a signal for transmitting an interfering signal and a related pilot on at least one different cell from the serving cells. The pilot transmitted on each serving cell can be a phase reference for the common multicast transmission, and can be the same signal transmitted on multiple serving cells. The signal indicating the relationship between cells can indicate which cells are serving cells transmitting a common multicast transmission. The signal indicating the relationship between cells can also indicate the identity of a cell, such as an extended serving cell, that is transmitting on the same resource as the serving cells. The signal indicating the relationship between cells can additionally indicate the identity of a cell, such as an extended serving cell, that does not transmit on the same resource as the serving cells. Fig. 4 is an exemplary flowchart 400 illustrating the operation of the network controller 140 according to another embodiment. In step 410, the flowchart begins. In step 420, the controller 140 can determine cells in which user equipment, such as terminals 120, reside that desire a common multicast service. In step 430, the controller 140 can select at least one serving cell 112 for transmitting the common multicast service, where the selection is based on the determination. In step 440, the network controller 140 can select at least one extended serving cell 114 from at least one serving cell 112 neighbor cell where no user equipment that desires the common multicast service resides, the extended serving cell influencing transmissions on the serving cell. Selecting at least one extended serving cell can include selecting the at least one extended serving cell 114 based on the at least one extended serving cell 114 having a large average interference with the serving cell 112. In step 450, the controller 140 can adjust transmission characteristics on the extended serving cell 114 to influence the transmission of the common multicast service on the selected at least one serving cell 112. The controller 140 can adjust the transmission characteristics to transmit the common multicast service on the extended serving cell 114 to influence the transmission of the common multicast service on the selected at least one serving cell 112. The controller 140 can also adjust transmission characteristics to block transmission on a resource of the extended serving cell 114, where transmitting on the resource would influence the transmission of the common multicast service on the selected at least one serving cell 112. In step 460, the controller 140 can indicate to the user equipment 120 on the selected at least one serving cell 112 that there is an unused resource on at least one neighbor cell. The controller 140 can also indicate, to the user equipment 120 on the selected at least one serving cell 112, the resource element used on the serving cell and indicate which extended serving cells 114 block the same resource. The controller 140 can also signal the power of a transmitted physical channel on an extended serving cell 114 to the user equipment 120 on the selected at least one serving cell 112. In step 470, the controller 140 can transmit the common multicast service on the selected at least one serving cell 112. While transmitting the common multicast service, the controller 140 can detect a change in a service area including the serving cell 112 and adjust an extended service area including the extended serving cell 114 based on detecting the change. In step 480, the flowchart 400 ends. Fig. 5 is an exemplary flowchart 500 illustrating the operation of a wireless communication device 200 according to another embodiment. In step 510, the flowchart begins. In step 520, the wireless communication device 200 can receive control information needed for reception of a local multicast service on a serving cell 112. This information can include information common to multiple serving or extended serving cells, such as a notification that a service transmission will begin, how the local multicast service is configured in the air interface, and other information. In step 530, the wireless communication device 200 can receive information regarding at least one extended serving cell 114, the extended serving cell 114 not including a wireless communication device desiring the local multicast service. In step 540, the wireless communication device 200 can adjust at least one receiver characteristic of the wireless communication device 200 based on the information regarding the at least one extended serving cell 114. Adjusting can include adjusting receiver characteristics based on the extended serving cell 114 blocking a resource element related to transmission of the local multicast service on the serving cell 112. Adjusting can additionally include applying antenna adaptive algorithm weights for combining multiple antenna signals. In step 550, the wireless communication device 200 can receive the common multicast transmission, can receive a common pilot signal from one cell, and can receive a common broadcast pilot signal from multiple cells. In step 560, the wireless communication device 200 can combine a transmission from the at least one extended serving cell 114 with a transmission from the serving cell 112. In step 570, the flowchart 500 can end. Fig. 6 is an exemplary illustration of a system 600, such as the system 100, according to another embodiment. The system 600 can include a terminal 610, such as a terminal 120, and cells 620, 630, 640, and 650. The cells 620, 630, and 640 may be located at the same site as the base stations containing serving cells 112. The cell 650 may be located in another base station containing cell 116 or an extended serving cell 114. The terminal 120 may be a wireless communication device 200 and can include an antenna array 615. In operation, multicasting radio systems can transmit the same signal from different cells or sites, such as cells 620, 630, and 640 in order to improve coverage. If a pilot is used for channel estimation purposes, the pilot portion of the transmitted signal can be normally transmitted in a similar or the same way as the data traffic so that the channel affecting data may be estimated from the pilot. Therefore, the pilot can be "related" to the data traffic transmission. For example, the pilot and data can be transmitted on similar antenna patterns, on similar frequencies, at close times, etc. This similarly transmitted pilot or "common broadcast pilot" may then be used to determine the channel that the data portion of the transmitted signal passes through, and so may be used in a receiver to decode the data. The terminal 610 may adapt its receiver to maximize the received signal to noise ratio (SNR) of a desired signal, or it may maximize the received signal to interference and noise ratio (SINR). Since the performance of a cellular radio telecommunication system is typically limited by interference, maximizing SINR generally gives better performance than maximizing SNR. A multiple antenna terminal 610 can be particularly effective at maximizing SINR, as it can adapt its antenna patterns such that the pattern magnitude is large in the direction of the desired transmission, and small in the direction of an interfering transmission. According to one embodiment, the present disclosure supports these maximum SINR receivers. A maximum SNR receiver is described to contrast its operation with maximum SINR receivers. An illustrative case is where the channel impulse response from a cell antenna 620 to a terminal 610 may be modeled as a single complex coefficient, which can be known as "flat Rayleigh fading." This flat fading model can be appropriate for narrow band transmissions, such as those often found in Frequency Division Multiple Access (FDMA) or Orthogonal Frequency Division Multiplexing (OFDM) systems, as well as in certain radio propagation environments. In these systems and environments, multicasting cells 620, 630, etc. may transmit the same signal at approximately the same times to the terminal 610, so that when they are sufficiently synchronized the transmissions can combine such that they appear to be a single transmission traveling through a channel that is the sum of the individual channels. The signal received from N of these multicasting transmitters at a terminal 610 with M antennas when both noise and interfering signals are present may be expressed as: Where: r is an (Mx1) column vector of the received signals and noise at each of the M terminal antennas from the N antennas transmitting the common desired signal h1 is an (Mx1) column vector of the channel impulse response between the ith (of N) antennas transmitting a desired signal and each of the terminal's antennas gj is an (Mx1) column vector of the channel impulse response between the jth (of L) antennas transmitting an interfering signal and each of the terminal's antennas. Each gj may be estimated from a pilot transmitted in the same way as the interfering signal, yj. hd is an (Mxl) column vector of the composite channel impulse response affecting the transmitted signal and it may be estimated from the common broadcast pilot. G is an (MxL) matrix, each column containing a gj n is an (Mxl) column vector of the noise at each of the M UE antennas x is the desired common transmitted signal from multiple cell antennas yj is the jth interfering signal y is an (Lxl) column vector of the interfering signals When a terminal's antenna array combiner with weights w is used to combine the received signals, r, the combiner output may be expressed: When we use the common assumption that the noise power on the received antennas 615 is the same, the received SINR, ?, at the antenna array combiner output, z , may be expressed as: Where: xH is complex conjugate transpose (the "Hermitian" transpose) of x A maximum SNR receiver matches the array combining weights to the composite channel, so in this case: Since the maximum SNR receiver only needs estimates of the composite channel impulse response, hd, in this case the terminal 610 does not need to estimate the channel impulse responses of the interference. However, maximum SNR receivers are only optimal in the presence of uncorrelated noise; so when correlated interference is present (i.e., when off diagonal elements of Rdd are not zero), other receivers such as a minimum mean squared error (MMSE) receiver can have better performance. The MMSE receiver uses array combining weights that take the form: RII may be calculated as above using estimates of gj, since each gj may be estimated from a pilot transmitted in the same way as the interfering signal, yj. Terminals typically need to know the identities (spreading sequences, scrambling codes, OFDM subcarriers, or the like) of the pilots used by the interfering transmitters, so that the gj may be estimated. This information may be signaled to the terminal 610, or may be known apriori by the terminal 610. When the information is signaled to the terminal 610, it is often desirable to provide the signaling about multiple interfering cells on a serving cell. This avoids the complexity involved when the terminal 610 receives control signaling from multiple cells. If the terminal 610 does not know the identities of the pilots used by the interfering transmitters, or if the pilots are not transmitted in the same way as the interfering signal (i.e., they are not "related to" nor "phase references" for the interfering signals), it can be difficult for the terminal 610 to use the interfering pilots to determine MMSE combining weights. Terminals often typically have to know which cells are transmitting interference to calculate RII . This information can be especially important when the network does not transmit interference on a cell near a terminal 610, since that nearby cell would otherwise likely be a strong interference source, and the terminal 610 would likely adapt its antenna pattern to attenuate it (reducing its ability to attenuate other interferes or to receive the desired common transmission). The network may therefore signal which cells do not transmit on a given channel, and so will not interfere with a common transmitted signal. Also, as indicated above, the terminal 610 can either be signaled identities of pilots that may be used as phase references for interfering signals, or the network transmissions can be constrained such that the terminal 610 knows the identities apriori. It is also useful for the terminal 610 to know which cells are those that are transmitting a common transmitted signal, so that they will not be considered as one of those providing interference (and therefore one of the L transmitters contributing to the interference terms in RII). This determination can be difficult when only common broadcast pilot is used, since the N common broadcast pilots from the N transmitters combine "in the air" to form a single received signal which reduces the identifiability of the individual transmitters. Therefore, the network may signal on a serving cell if a nearby cell is one of those transmitting a common transmitted signal. This knowledge of desired and interfering transmitters and their related pilots can enable improved terminal SINR performance over the case where only a common broadcast pilot is used (and where interference can not be controlled as effectively). The system 600 further illustrates the use of desired and interfering transmitter and pilot information for the case where a maximum SINR receiver is used. The terminal's antenna pattern 615 can be adapted to be large in the direction of the combined transmission, while it is small in the direction of the interfering transmitter 650. The combined transmission can appear to the terminal 610 to be from a single transmitter and is illustrated as coming from a single direction. While this is not required in the most literal sense, since adaptive arrays are capable of using a single degree of freedom to adapt to a coherent transmission such as the combined transmission contemplated in the preferred embodiment, it is reasonable for the purposes of illustration in the system 600. Fig. 7 is an exemplary flowchart 700 illustrating the operation of the network controller 140 according to another embodiment. In step 710, the flowchart begins. Fig. 8 is an exemplary flowchart 800 illustrating the operation of a wireless communication device 200 according to another embodiment. In step 810, the flowchart begins. In step 820, the wireless communication device 200 can receive information regarding serving cells 112 that are transmitting a common multicast transmission. In step 830, the wireless communication device 200 can adapt a receiver characteristic in response to receiving the information regarding the serving cells 112. For example, the wireless communication device 200 can adapt a receiver or an antenna array in response to receiving the information regarding the serving cells 112. As a further example, the wireless communication device 200 can attenuate an interfering signal by adapting its receiver to attenuate interference using the information regarding serving cells. In step 840, the wireless communication device 200 can receive the common multicast transmission, at least a portion of which is transmitted on the same resource on multiple serving cells 112. In step 850, the wireless communication device 200 can receive a common broadcast pilot signal related to the common multicast transmission, the common broadcast pilot signal being common to multiple cells. In steps 840 and 850, the wireless communication device 200 can also receive an interfering signal and a related pilot from a different cell 114 from the serving cells 112. In step 860, the wireless communication device 200 can adapt a receiver characteristic in response to receiving the broadcast pilot. For example, the wireless communication device 200 can adapt a receiver or an antenna array in response to receiving the broadcast pilot. As a further example, the wireless communication device 200 can attenuate an interfering signal by adapting the receiver to attenuate interference using the information regarding serving cells and the common broadcast pilot signal and the pilot related to the interfering signal. In step 870, the wireless communication device 200 can decode the common multicast transmission. In step 880, the wireless communication device 200 can present the common multicast transmission to a user of the wireless device via a user interface. In step 890, the flowchart 800 can end. Thus, the present disclosure can provide neighbor assisted localized multicast. For example, when a session starts, counting can be performed by a network. Counting can be performed by having each cell report its user status, such as radio bearer status to a controller such as a Radio Network Controller. The cells wherein users reside that desire a multicast session can form a service area. The controller can choose appropriate cells except the cells in the serving area, which are the candidates for the strongest interference for the cells in the serving area. These cells can form an extended serving area. The controller can control the cells in the extended serving area to either broadcast the same data as the cells in the serving area, in the case that cell power is available or block resource element that is used by the cell in the serving area, in the case that cell power is unavailable. The service area may change by a user moving between cells, by a user joining a session after it starts, or by any other similar event. If the service area changes during the session transmission, the controller may adjust the extended serving area as well. The present disclosure can allow interference to be more finely controlled than existing simulcast or single frequency networks. For example, both the coverage area and interference sources can be explicitly controlled. This can allow greater spectral efficiency per unit area and better coverage due to the precise control over interference and a terminal's knowledge of desired and interfering sources. For example, a controller can signal information on which neighbor cells have reserved and are not transmitting on a resource element that a serving cell is transmitting on. This information can allow the terminal to configure an optimum receiver in the terminal. The controller can also signal which neighbor cells are transmitting identically on a resource element, that a serving cell is transmitting on. For example, transmitting identically on a resource element can mean that the signals are transmitted such that when the channel combines the signals from any two cells, the terminal cannot distinguish the transmissions from the two cells when the channels are within a scale factor of each other. This can use identical scrambling, spreading, interleaving, or the like. The controller can signal the information above on the serving cell. The method of this disclosure is preferably implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an ASIC or other integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or the like. In general, any device on which resides a finite state machine capable of In step 720, the controller 140 can determine cells in which user equipment, such as terminals 120, reside that desire a common multicast service and select at least one serving cell 112 for transmitting the common multicast service. In step 730, the controller 140 can send a signal to user equipment indicating the relationship between cells with respect to serving cells 112 transmitting a common multicast transmission. The signal can be a signal indicating which cells are serving cells 112 transmitting a common multicast transmission and/or a signal indicating the identity of another cell, such as an extended serving cell 114, which is transmitting on the same resource as the serving cells. In step 740, the controller 140 can transmit at least a portion of the common multicast transmission on the same resource on each serving cell 112. The common multicast transmission can be determined from a single information stream, such as from a media content server, for broadcast to multiple users at multiple locations. The common multicast transmission can be transmitted on the serving cells 112 using the same physical layer attributes on each serving cell 112. The same physical layer attributes can be the same resource element, as well as the same spreading, the same channel coding, the same error detection coding (such as a cyclic redundancy check on the payload data), the same time frequency resources, the same frequency hopping pattern, and the like. In step 750, the controller 140 can transmit a pilot signal on each serving cell 112, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell 112. The pilot transmitted on each serving cell 112 can be a phase reference for the common multicast transmission and can be the same signal transmitted on multiple serving cells 112. In step 760, the controller 140 can transmit an interfering signal and a related pilot on at least one different cell from the serving cells, such as an extended serving cell 114. In step 770, the controller 140 can signal to a transmitting base station an indicator indicating not to transmit on a resource on a non-serving cell, such as on an extended serving cell 114. In step 780, the controller 140 can signal to user equipment the identity of a cell, such as an extended serving cell 114, which does not transmit on the same resource as the serving cells. The same resource on each serving cell 112 can be the same slot, the same frequency, the same period, the same Walsh codes, and the like on each serving cell 112. In step 790, the flowchart 700 can end. implementing the flowcharts shown in the Figures may be used to implement the processor functions of this disclosure. While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, the preferred embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure. AMENDED CLAIMS received by the International Bureau on 30 March 2007 (30.03.2007) 1. A network controller comprising: a processor configured to control the operations of the network controller; a serving cell signaling module coupled to the processor configured to signal to user equipment a signal indicating the relationship between cells with respect to serving cells transmitting a common multicast transmission; and a network connection coupled to the processor the network connection configured to send a signal for transmitting at least a portion of the common multicast transmission on the same resource element on each serving cell, the network connection configured to send a signal for transmitting a pilot signal on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell, the network connection configured to send a signal for transmitting an interfering signal and a related pilot on at least one different cell from the serving cells. 2. The network controller according to claim 1, wherein the pilot transmitted on at least one serving cell is a phase reference for the common multicast transmission, and is the same signal transmitted on multiple serving cells. 3. The network controller according to claim 1, wherein the signal Indicating the relationship between cells indicates which cells are serving cells transmitting a common multicast transmission. 4. The network controller according to claim 1, wherein the signal indicating the relationship between cells indicates the identity of a cell that is transmitting on the same resource as the serving cells, 5. A wireless communication device comprising: a controller configured to control the operations of the wireless device; a receiver configured to receive information regarding serving cells that are transmitting a common multicast transmission, the receiver also configured to receive the common multicast transmission, at least a portion of which is transmitted on the same resource on multiple serving cells, the receiver also configured to receive a common broadcast pilot signal related to the common multicast transmission, the common broadcast pilot signal being common to multiple cells; and a multicast transmission decoder configured to decode the common multicast transmission. 6. The wireless communication device according to claim 5, further comprising a receiver characteristic adjustment module configured to adapt characteristics of the receiver in response to receiving the information regarding the serving cells. 7. The wireless communication device according to claim 6, further comprising an antenna array coupled to the receiver, wherein the receiver characteristic adjustment module is further configured to adapt the antenna array in response to receiving the information regarding the serving cells. 8. The wireless communication device according to claim 5, further comprising a user interface configured to present the common multicast transmission to a user of the wireless device. 9. A method in a wireless network, the method comprising; signaling to user equipment a signal indicating the relationship between at least one cell with respect to at least one serving cell transmitting a common multicast transmission; transmitting at least a portion of the common multicast transmission on the same resource on the at least one serving cell; and transmitting a pilot signal on the at least one serving cell, the pilot signal related to the at least a portion of the common multicast transmission on the at least one serving cell; wherein a cell different from the at least one serving cell transmits an interfering signal and a related pilot. 10. A method in a wireless device, the method comprising: receiving information regarding serving cells that are transmitting a common multicast transmission; receiving the common multicast transmission, at least a portion of which is transmitted on the same resource element on multiple serving cells; receiving a common broadcast pilot signal related to the common multicast transmission, the common broadcast pilot signal being common to multiple cells; and decoding the common multicast transmission. A method and apparatus for neighbor assisted combining for localized multicast services. User equipment (120) is sent a signal (730) indicating the relationship between cells with respect to serving cells (112) transmitting a common multicast transmission. At least a portion of the common multicast transmission is transmitted (740) on the same resource on each serving cell. A pilot signal is transmitted (750) on each serving cell, the pilot signal related to the at least a portion of the common multicast transmission on each serving cell. An interfering signal and a related pilot are transmitted (760) on at least one different cell (114) from the serving cells.

Full Text

APPARATUS AND METHOD FOR NEIGHBOR ASSISTED COMBINING FOR
MULTICAST SERVICES
BACKGROUND
1. Technical Field
The present disclosure is directed to a method and apparatus for neighbor
assisted combining for localized multicast services. More particularly, the present
disclosure is directed to using at least one serving cell and at least one extended
serving cell for broadcast and multicast services.
2. Description of Related Art
Presently, to deliver a multicast/broadcast stream in the Radio Access network
(RAN) efficiently, two possible methods can be used. One is simulcast and the other
is localized multicast. In simulcast mode, a Multimedia Broadcast Multicast Service
(MBMS) service area is identical to the RAN system coverage area. All the cells
broadcast the same data using the same physical layer resources (denoted "resource
elements" or "resources" for short). A resource element is a unit of physical layer
resource into which data can be multiplexed. A resource element can be one of, a
multiplicity of, or a combination of, a time slot, an orthogonal spreading function such
as a Walsh code, a subcarrier (such as is used in Orthogonal Frequency Division
Multiplexing, or "OFDM"), or the like. Since identical transmissions from multiple
cells on the same resource can combine such that they appear as a single transmission,
in systems such as an OFDM based Enhanced MBMS (EMBMS), this could reduce
the inter-cell interference if the allocated resource element is identical, which can
improve transmission efficiency as measured in Bits/Hz. For a service with a very
large number of users and when the service is widely distributed in the RAN,
simulcast can be a very efficient transmission technique. For example, simulcast can
be useful for transmission of weather reports, music, movies, etc.
Simulcast is not efficient if the service area is much smaller than the system
coverage area. For example, if the service is mostly focused in selected multiple cells,
such as for clip replay for football stadiums, sport centers, local weather reports, or the
like, it is not good to turn on all the cells in the system to deliver the localized service
to just the selected cells. Most of these MBMS services may fall into this category of
localized MBMS. In other words, simulcast is not an efficient way to improve
efficiency as measured in Bits/Hz/km2. For the localized MBMS service, counting
can be used to determine the user status of the cells, such as to determine which cells
contain users who desire the service. Then an efficient radio bearer will be
established in the appropriate cells to deliver the MBMS service.
Unfortunately, during a localized multicast session, neighboring cells interfere
with the localized service area cells. For example, neighbor cells may transmit on the
same resource element as the serving cells, which will interfere with the common
multicast transmission. Thus, there is a need for a method and apparatus for neighbor
assisted combining for localized multicast services.
SUMMARY
A method and apparatus for neighbor assisted combining for localized
multicast services. User equipment is sent a signal indicating the relationship between
cells with respect to serving cells transmitting a common multicast transmission. At
least a portion of the common multicast transmission is transmitted on the same
resource on each serving cell. A pilot signal is transmitted on each serving cell, the
pilot signal related to the at least a portion of the common multicast transmission on
each serving cell. An interfering signal and a related pilot are transmitted on at least
one different cell from the serving cells.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments of the present disclosure will be described with reference to
the following figures, wherein like numerals designate like elements, and wherein:
Fig. 1 is an exemplary block diagram of a system according to one
embodiment;
Fig. 2 is an exemplary block diagram of a wireless communication device
according to one embodiment;
Fig. 3 is an exemplary block diagram of a controller according to one
embodiment;
Fig. 4 is an exemplary flowchart illustrating the operation of a network
controller according to one embodiment;
Fig. 5 is an exemplary flowchart illustrating the operation of a wireless
communication device according to one embodiment;
Fig. 6 is an exemplary illustration of a system according to another
embodiment;
Fig. 7 is an exemplary flowchart illustrating the operation of a network
controller according to another embodiment; and
Fig. 8 is an exemplary flowchart illustrating the operation of a wireless
communication device according to another embodiment.
DETAILED DESCRIPTION
Fig. 1 is an exemplary block diagram of a system 100 according to one
embodiment. The system 100 can include a network controller 140, a network 110,
and at least one terminal 120. The terminal 120 may be a wireless communication
device, such as a wireless telephone, a cellular telephone, a personal digital assistant, a
pager, a personal computer, a selective call receiver, or any other device that is
capable of sending and receiving communication signals on a network including
wireless network. The network can include base stations with cells (such as
transmitters that serve part or all of an area covered by a base station) 112, 114, and
116. These cells can include serving cells 112 and extended serving cells 114. In the
exemplary embodiment, one cell per base station is assumed. However, multiple cells
may be present per base station.
In an exemplary embodiment, the network controller 140 is connected to the
network 110. The controller 140 may be located at a base station, at a radio network
controller, at a multicast transmission server, anywhere else on the network 110,
and/or may be distributed throughout various resources on the network 110. The
network 110 may include any type of network that is capable of sending and receiving
signals, such as wireless signals. For example, the network 110 may include a
wireless telecommunications network, a cellular telephone network, a satellite
communications network, and other like communications systems. Furthermore, the
network 110 may include more than one network and may include a plurality of
different types of networks. Thus, the network 110 may include a plurality of data
networks, a plurality of telecommunications networks, a combination of data and
telecommunications networks and other like communication systems capable of
sending and receiving communication signals.
In operation, the controller 140 can determine cells 112 in which user
equipment, such as terminals 120, reside that desire a common multicast service. A
terminal resides in a cell if that cell can be received better than other cells. For
example due to variability in radio propagation, the terminal is not necessarily closer
to the base station containing the cell than to other base stations. The controller 140
can select at least one serving cell 112 for transmitting the common multicast service
where the selection can be based on the determination. The controller 140 can select
at least one extended serving cell 114 from at least one serving cell neighbor cell
which does not have user equipment that desires the common multicast service, the
extended serving cell 114 influencing transmissions on the serving cell 112. The
controller 140 can transmit the common multicast service on the selected at least one
serving cell 112.
According to a related embodiment, the controller 140 can signal to user
equipment, such as terminals 120, a signal indicating the relationship between cells
with respect to the serving cells 112 transmitting a common multicast transmission.
The controller can transmit at least a portion of the common multicast transmission on
the same resource on each serving cell 112. The controller 140 can transmit a pilot
signal on each serving cell 112, the pilot signal related to the at least a portion of the
common multicast transmission on each serving cell 112. The controller 140 can
transmit an interfering signal and a related pilot on at least one different cell 114 from
the serving cells 112.
For example, in a Multimedia Broadcast Multicast Service (MBMS), when
one MBMS session begins, the controller 140 can perform counting to determine the
user status of all the cells under the controller 140. If one cell has enough users, such
as terminals 120, the cell can be a serving cell 112 and a broadcast mode can be
established for the serving cell 112. The threshold for enough users may be a single
user. If there are no users in a cell, such as in cells 114 and 116, the cell may not
broadcast the data. A user, such as a terminal 112, can read Multicast Control
Channel (MCCH) messages to determine if and how to combine a neighbor cell's 114
stream with its serving cell's 112 stream in order to obtain the diversity gain and/or
the power gain.
To elaborate, in Enhanced MBMS (EMBMS), interference may only come
from other cells. This can be a major bottleneck for system capacity. If the controller
140 can control the neighboring cells with largest average interference to broadcast
the same data using the same resource element or at least not use that resource
element for other data transmissions, the interference level can be greatly reduced.
This can significantly increase the system capacity. Counting can be performed when
the session begins. Each cell can report its user status to the controller 140. These
serving cells 112 form the service area. The controller 140 can then choose
appropriate cells aside from the serving cells 112 that are the candidates for the
strongest interference for the cells in the serving area. This cells form extended
serving cells 114 in an extended serving area. The controller 140 can then control the
extended serving cells 114 in the extended serving area to either broadcast the same
data as the serving cells 112 in the serving area, in the case that cell power is available
in an extended serving cell 114, or block the resource element that is used by an
extended serving cell 114 in the case that cell power is unavailable at the extended
serving cell 114. If the service area changes, such as by a user moving between cells,
by a late joining user, or the like, during the session transmission, the controller 140
can adjust the extended serving area accordingly.
Fig. 2 is an exemplary block diagram of a wireless communication device 200,
such as the terminal 120, according to one embodiment. The wireless communication
device 200 can include a housing 210, a controller 220 coupled to the housing 210,
audio input and output circuitry 230 coupled to the housing 210, a display 240
coupled to the housing 210, a transceiver 250 coupled to the housing 210, a user
interface 260 coupled to the housing 210, a memory 270 coupled to the housing 210,
and at least one antenna 280 coupled to the housing 210 and the transceiver 250. At
least one other antenna 282 may be coupled to the transceiver 250 to create an antenna
array. The wireless communication device 200 can also include a multicast control
information module 290, a receiver characteristic adjustment module 292, and a
multicast transmission decoder 294. The multicast control information module 290,
the receiver characteristic adjustment module 292, and the multicast transmission
decoder 294 can be coupled to the controller 220, can reside within the controller 220,
can reside within the memory 270, can be autonomous modules, can be software, can
be hardware, or can be in any other format useful for a module on a wireless
communication device 200.
The display 240 can be a liquid crystal display (LCD), a light emitting diode
(LED) display, a plasma display, or any other means for displaying information. The
transceiver 250 may include a transmitter and/or a receiver. The audio input and
output circuitry 230 can include a microphone, a speaker, a transducer, or any other
audio input and output circuitry. The user interface 260 can include a keypad,
buttons, a touch pad, a joystick, an additional display, or any other device useful for
providing an interface between a user and an electronic device. The memory 270 may
include a random access memory, a read only memory, an optical memory, a
subscriber identity module memory, or any other memory that can be coupled to a
wireless communication device.
In operation, the controller 220 can control the operations of the wireless
communication device 200. The multicast control information module 290 can
receive control information needed for reception of a local multicast service on a
serving cell. This information can include information common to multiple serving or
extended serving cells, such as a notification that a service transmission will begin,
how the local multicast service is configured in the air interface, and other
information. The transceiver 250 can receive information regarding at least one
extended serving cell, the extended serving cell being a cell where no wireless
communication device desiring the local multicast service resides. The receiver
characteristic adjustment module 292 can adjust at least one receiver characteristic of
the wireless communication device transceiver 250 based on the information
regarding the at least one extended serving cell. For example, the receiver
characteristic adjustment module 294 can adjust at least one receiver characteristic
based on the extended serving cell blocking a resource element related to transmission
of the local multicast service on the serving cell. The receiver characteristic
adjustment module 292 can also adjust at least one receiver characteristic by applying
antenna adaptive algorithm weights for combining multiple antenna signals from the
antennas 280 and 282.
In operation according to a related embodiment, the receiver in the transceiver
250 can receive information regarding serving cells that are transmitting a common
multicast transmission. The receiver can also receive the common multicast
transmission, at least a portion of which is transmitted on the same resource on
multiple serving cells. The receiver can additionally receive a common broadcast
pilot signal related to the common multicast transmission, the common broadcast pilot
signal being common to multiple cells. The multicast transmission decoder 294 can
decode the common multicast transmission. The receiver characteristic adjustment
module 292 can adapt characteristics of the receiver in response to receiving the
information regarding the serving cells. The antennas 280 and 282 can comprise an
antenna array. The receiver characteristic adjustment module 292 can adapt the
antenna array in response to receiving the information regarding the serving cells. A
user interface can present the common multicast transmission to a user of the wireless
device 200. For example, the common multicast transmission can be presented via
the display 240, the audio input and output 230 and/or the user interface 260.
Fig. 3 is an exemplary block diagram of a controller 300, such as the network
controller 140, according to one embodiment. The controller 300 can include a
housing 310, a processor 320 coupled to the housing 310, a network connection 350
coupled to the processor 320, media content storage 360 coupled to the processor 320,
and a memory 370 coupled to the processor 320. The media content storage 360 may
be autonomous or may be located in the memory 370. The controller 300 can also
include a counting module 390, a serving cell selection module 392, an extended
serving cell selection module 394, a serving cell signaling module 396, and a
transmission characteristic adjustment module 398. The counting module 390, the
serving cell selection module 392, the extended serving cell selection module 394, the
serving cell signaling module 396, and the transmission characteristic adjustment
module 398 can reside within the controller 320, can reside within the memory 370,
can be autonomous modules, can be software, can be hardware, or can be in any other
format useful for a module on a controller. Also, each element of the controller 300
may be located at the network controller 140 or may be distributed throughout the
network 110. For example, the media content 360 may be located at a media content
provider, other elements may be located at different network controllers, and other
elements may be located at different base stations on the network 110.
In operation, the processor 320 can control the operations of the controller
300. The counting module 390 can determine cells in which user equipment resides
that desire a common multicast service. The serving cell selection module 392 can
select at least one serving cell for transmitting the common multicast service, where
the selection is based on the determination. The extended serving cell selection
module 394 can select at least one extended serving cell from at least one serving cell
neighbor cell which where no user equipment resides that desires the common
multicast service, the extended serving cell influencing transmissions on the serving
cell. The extended serving cell selection module 394 can also select the at least one
extended serving cell based on the at least one extended serving cell having a large
average interference with the serving cell. The network connection 350 can send the
common multicast service for transmission on the selected at least one serving cell.
The transmission characteristic adjustment module 398 can adjust
transmission characteristics on the extended serving cell to influence the transmission
of the common multicast service on the selected at least one serving cell. For
example, the transmission characteristic adjustment module 398 can adjust the
transmission characteristics to transmit the common multicast service on the extended
serving cell to influence the transmission of the common multicast service on the
selected at least one serving cell. As another example, the transmission characteristic
adjustment module 398 can also block transmission on a resource of the extended
serving cell, where transmitting on the resource would influence the transmission of
the common multicast service on the selected at least one serving cell. The processor
320 can indicate, via the network connection 350, to user equipment on the selected at
least one serving cell that there is an unused resource on at least one neighbor cell.
The processor 320 can also indicate, via the network connection 350, to the user
equipment on the selected at least one serving cell, the resource element used on the
serving cell and which extended serving cells block the same resource. The user
equipment can then adjust receiver characteristics and/or antenna characteristics more
efficiently based on the knowledge of transmission characteristics of the neighbor
cells. The processor 320 can detect a need to change the service area including adding
or removing a serving cell and the extended serving cell selection module 394 can
adjust an extended service area including adding or removing an extended serving cell
based on the processor 320 detecting the change.
In operation according to a related embodiment, the serving cell signaling
module 396 can signal to user equipment a signal indicating the relationship between
cells with respect to serving cells transmitting a common multicast transmission. The
network connection 350 can send a signal for transmitting at least a portion of the
common multicast transmission on the same resource on each serving cell. The
network connection 350 sends a signal for transmitting a pilot signal on each serving
cell, the pilot signal related to the at least a portion of the common multicast
transmission on each serving cell, The network connection 350 can send a signal for
transmitting an interfering signal and a related pilot on at least one different cell from
the serving cells. The pilot transmitted on each serving cell can be a phase reference
for the common multicast transmission, and can be the same signal transmitted on
multiple serving cells. The signal indicating the relationship between cells can
indicate which cells are serving cells transmitting a common multicast transmission.
The signal indicating the relationship between cells can also indicate the identity of a
cell, such as an extended serving cell, that is transmitting on the same resource as the
serving cells. The signal indicating the relationship between cells can additionally
indicate the identity of a cell, such as an extended serving cell, that does not transmit
on the same resource as the serving cells.
Fig. 4 is an exemplary flowchart 400 illustrating the operation of the network
controller 140 according to another embodiment. In step 410, the flowchart begins.
In step 420, the controller 140 can determine cells in which user equipment, such as
terminals 120, reside that desire a common multicast service. In step 430, the
controller 140 can select at least one serving cell 112 for transmitting the common
multicast service, where the selection is based on the determination. In step 440, the
network controller 140 can select at least one extended serving cell 114 from at least
one serving cell 112 neighbor cell where no user equipment that desires the common
multicast service resides, the extended serving cell influencing transmissions on the
serving cell. Selecting at least one extended serving cell can include selecting the at
least one extended serving cell 114 based on the at least one extended serving cell 114
having a large average interference with the serving cell 112.
In step 450, the controller 140 can adjust transmission characteristics on the
extended serving cell 114 to influence the transmission of the common multicast
service on the selected at least one serving cell 112. The controller 140 can adjust the
transmission characteristics to transmit the common multicast service on the extended
serving cell 114 to influence the transmission of the common multicast service on the
selected at least one serving cell 112. The controller 140 can also adjust transmission
characteristics to block transmission on a resource of the extended serving cell 114,
where transmitting on the resource would influence the transmission of the common
multicast service on the selected at least one serving cell 112. In step 460, the
controller 140 can indicate to the user equipment 120 on the selected at least one
serving cell 112 that there is an unused resource on at least one neighbor cell. The
controller 140 can also indicate, to the user equipment 120 on the selected at least one
serving cell 112, the resource element used on the serving cell and indicate which
extended serving cells 114 block the same resource. The controller 140 can also
signal the power of a transmitted physical channel on an extended serving cell 114 to
the user equipment 120 on the selected at least one serving cell 112. In step 470, the
controller 140 can transmit the common multicast service on the selected at least one
serving cell 112. While transmitting the common multicast service, the controller 140
can detect a change in a service area including the serving cell 112 and adjust an
extended service area including the extended serving cell 114 based on detecting the
change. In step 480, the flowchart 400 ends.
Fig. 5 is an exemplary flowchart 500 illustrating the operation of a wireless
communication device 200 according to another embodiment. In step 510, the
flowchart begins. In step 520, the wireless communication device 200 can receive
control information needed for reception of a local multicast service on a serving cell
112. This information can include information common to multiple serving or
extended serving cells, such as a notification that a service transmission will begin,
how the local multicast service is configured in the air interface, and other
information. In step 530, the wireless communication device 200 can receive
information regarding at least one extended serving cell 114, the extended serving cell
114 not including a wireless communication device desiring the local multicast
service. In step 540, the wireless communication device 200 can adjust at least one
receiver characteristic of the wireless communication device 200 based on the
information regarding the at least one extended serving cell 114. Adjusting can
include adjusting receiver characteristics based on the extended serving cell 114
blocking a resource element related to transmission of the local multicast service on
the serving cell 112. Adjusting can additionally include applying antenna adaptive
algorithm weights for combining multiple antenna signals. In step 550, the wireless
communication device 200 can receive the common multicast transmission, can
receive a common pilot signal from one cell, and can receive a common broadcast
pilot signal from multiple cells. In step 560, the wireless communication device 200
can combine a transmission from the at least one extended serving cell 114 with a
transmission from the serving cell 112. In step 570, the flowchart 500 can end.
Fig. 6 is an exemplary illustration of a system 600, such as the system 100,
according to another embodiment. The system 600 can include a terminal 610, such
as a terminal 120, and cells 620, 630, 640, and 650. The cells 620, 630, and 640 may
be located at the same site as the base stations containing serving cells 112. The cell
650 may be located in another base station containing cell 116 or an extended serving
cell 114. The terminal 120 may be a wireless communication device 200 and can
include an antenna array 615.
In operation, multicasting radio systems can transmit the same signal from
different cells or sites, such as cells 620, 630, and 640 in order to improve coverage.
If a pilot is used for channel estimation purposes, the pilot portion of the transmitted
signal can be normally transmitted in a similar or the same way as the data traffic so
that the channel affecting data may be estimated from the pilot. Therefore, the pilot
can be "related" to the data traffic transmission. For example, the pilot and data can
be transmitted on similar antenna patterns, on similar frequencies, at close times, etc.
This similarly transmitted pilot or "common broadcast pilot" may then be used to
determine the channel that the data portion of the transmitted signal passes through,
and so may be used in a receiver to decode the data.
The terminal 610 may adapt its receiver to maximize the received signal to
noise ratio (SNR) of a desired signal, or it may maximize the received signal to
interference and noise ratio (SINR). Since the performance of a cellular radio
telecommunication system is typically limited by interference, maximizing SINR
generally gives better performance than maximizing SNR. A multiple antenna
terminal 610 can be particularly effective at maximizing SINR, as it can adapt its
antenna patterns such that the pattern magnitude is large in the direction of the desired
transmission, and small in the direction of an interfering transmission. According to
one embodiment, the present disclosure supports these maximum SINR receivers.
A maximum SNR receiver is described to contrast its operation with
maximum SINR receivers. An illustrative case is where the channel impulse response
from a cell antenna 620 to a terminal 610 may be modeled as a single complex
coefficient, which can be known as "flat Rayleigh fading." This flat fading model can
be appropriate for narrow band transmissions, such as those often found in Frequency
Division Multiple Access (FDMA) or Orthogonal Frequency Division Multiplexing
(OFDM) systems, as well as in certain radio propagation environments. In these
systems and environments, multicasting cells 620, 630, etc. may transmit the same
signal at approximately the same times to the terminal 610, so that when they are
sufficiently synchronized the transmissions can combine such that they appear to be a
single transmission traveling through a channel that is the sum of the individual
channels. The signal received from N of these multicasting transmitters at a terminal
610 with M antennas when both noise and interfering signals are present may be
expressed as:

Where:
r is an (Mx1) column vector of the received signals and noise at each of the M
terminal antennas from the N antennas transmitting the common desired signal
h1 is an (Mx1) column vector of the channel impulse response between the ith (of
N) antennas transmitting a desired signal and each of the terminal's antennas
gj is an (Mx1) column vector of the channel impulse response between the jth (of
L) antennas transmitting an interfering signal and each of the terminal's
antennas. Each gj may be estimated from a pilot transmitted in the same way as
the interfering signal, yj.
hd is an (Mxl) column vector of the composite channel impulse response affecting
the transmitted signal and it may be estimated from the common broadcast pilot.
G is an (MxL) matrix, each column containing a gj
n is an (Mxl) column vector of the noise at each of the M UE antennas
x is the desired common transmitted signal from multiple cell antennas
yj is the jth interfering signal
y is an (Lxl) column vector of the interfering signals
When a terminal's antenna array combiner with weights w is used to combine
the received signals, r, the combiner output may be expressed:

When we use the common assumption that the noise power on the received
antennas 615 is the same, the received SINR, ?, at the antenna array combiner
output, z , may be expressed as:

Where:

xH is complex conjugate transpose (the "Hermitian" transpose) of x

A maximum SNR receiver matches the array combining weights to the
composite channel, so in this case:

Since the maximum SNR receiver only needs estimates of the composite
channel impulse response, hd, in this case the terminal 610 does not need to estimate
the channel impulse responses of the interference. However, maximum SNR
receivers are only optimal in the presence of uncorrelated noise; so when correlated
interference is present (i.e., when off diagonal elements of Rdd are not zero), other
receivers such as a minimum mean squared error (MMSE) receiver can have better
performance. The MMSE receiver uses array combining weights that take the form:

RII may be calculated as above using estimates of gj, since each gj may be
estimated from a pilot transmitted in the same way as the interfering signal, yj.
Terminals typically need to know the identities (spreading sequences, scrambling
codes, OFDM subcarriers, or the like) of the pilots used by the interfering transmitters,
so that the gj may be estimated. This information may be signaled to the terminal
610, or may be known apriori by the terminal 610. When the information is signaled
to the terminal 610, it is often desirable to provide the signaling about multiple
interfering cells on a serving cell. This avoids the complexity involved when the
terminal 610 receives control signaling from multiple cells. If the terminal 610 does
not know the identities of the pilots used by the interfering transmitters, or if the pilots
are not transmitted in the same way as the interfering signal (i.e., they are not "related
to" nor "phase references" for the interfering signals), it can be difficult for the
terminal 610 to use the interfering pilots to determine MMSE combining weights.
Terminals often typically have to know which cells are transmitting
interference to calculate RII . This information can be especially important when the
network does not transmit interference on a cell near a terminal 610, since that nearby
cell would otherwise likely be a strong interference source, and the terminal 610
would likely adapt its antenna pattern to attenuate it (reducing its ability to attenuate
other interferes or to receive the desired common transmission). The network may
therefore signal which cells do not transmit on a given channel, and so will not
interfere with a common transmitted signal. Also, as indicated above, the terminal
610 can either be signaled identities of pilots that may be used as phase references for
interfering signals, or the network transmissions can be constrained such that the
terminal 610 knows the identities apriori.
It is also useful for the terminal 610 to know which cells are those that are
transmitting a common transmitted signal, so that they will not be considered as one
of those providing interference (and therefore one of the L transmitters contributing to
the interference terms in RII). This determination can be difficult when only
common broadcast pilot is used, since the N common broadcast pilots from the N
transmitters combine "in the air" to form a single received signal which reduces the
identifiability of the individual transmitters. Therefore, the network may signal on a
serving cell if a nearby cell is one of those transmitting a common transmitted signal.
This knowledge of desired and interfering transmitters and their related pilots
can enable improved terminal SINR performance over the case where only a common
broadcast pilot is used (and where interference can not be controlled as effectively).
The system 600 further illustrates the use of desired and interfering transmitter
and pilot information for the case where a maximum SINR receiver is used. The
terminal's antenna pattern 615 can be adapted to be large in the direction of the
combined transmission, while it is small in the direction of the interfering transmitter
650. The combined transmission can appear to the terminal 610 to be from a single
transmitter and is illustrated as coming from a single direction. While this is not
required in the most literal sense, since adaptive arrays are capable of using a single
degree of freedom to adapt to a coherent transmission such as the combined
transmission contemplated in the preferred embodiment, it is reasonable for the
purposes of illustration in the system 600.
Fig. 7 is an exemplary flowchart 700 illustrating the operation of the network
controller 140 according to another embodiment. In step 710, the flowchart begins.
Fig. 8 is an exemplary flowchart 800 illustrating the operation of a wireless
communication device 200 according to another embodiment. In step 810, the
flowchart begins. In step 820, the wireless communication device 200 can receive
information regarding serving cells 112 that are transmitting a common multicast
transmission. In step 830, the wireless communication device 200 can adapt a
receiver characteristic in response to receiving the information regarding the serving
cells 112. For example, the wireless communication device 200 can adapt a receiver
or an antenna array in response to receiving the information regarding the serving cells
112. As a further example, the wireless communication device 200 can attenuate an
interfering signal by adapting its receiver to attenuate interference using the
information regarding serving cells. In step 840, the wireless communication device
200 can receive the common multicast transmission, at least a portion of which is
transmitted on the same resource on multiple serving cells 112. In step 850, the
wireless communication device 200 can receive a common broadcast pilot signal
related to the common multicast transmission, the common broadcast pilot signal
being common to multiple cells. In steps 840 and 850, the wireless communication
device 200 can also receive an interfering signal and a related pilot from a different
cell 114 from the serving cells 112. In step 860, the wireless communication device
200 can adapt a receiver characteristic in response to receiving the broadcast pilot.
For example, the wireless communication device 200 can adapt a receiver or an
antenna array in response to receiving the broadcast pilot. As a further example, the
wireless communication device 200 can attenuate an interfering signal by adapting the
receiver to attenuate interference using the information regarding serving cells and the
common broadcast pilot signal and the pilot related to the interfering signal. In step
870, the wireless communication device 200 can decode the common multicast
transmission. In step 880, the wireless communication device 200 can present the
common multicast transmission to a user of the wireless device via a user interface.
In step 890, the flowchart 800 can end.
Thus, the present disclosure can provide neighbor assisted localized multicast.
For example, when a session starts, counting can be performed by a network.
Counting can be performed by having each cell report its user status, such as radio
bearer status to a controller such as a Radio Network Controller. The cells wherein
users reside that desire a multicast session can form a service area. The controller can
choose appropriate cells except the cells in the serving area, which are the candidates
for the strongest interference for the cells in the serving area. These cells can form an
extended serving area. The controller can control the cells in the extended serving
area to either broadcast the same data as the cells in the serving area, in the case that
cell power is available or block resource element that is used by the cell in the serving
area, in the case that cell power is unavailable. The service area may change by a user
moving between cells, by a user joining a session after it starts, or by any other similar
event. If the service area changes during the session transmission, the controller may
adjust the extended serving area as well.
The present disclosure can allow interference to be more finely controlled than
existing simulcast or single frequency networks. For example, both the coverage area
and interference sources can be explicitly controlled. This can allow greater spectral
efficiency per unit area and better coverage due to the precise control over interference
and a terminal's knowledge of desired and interfering sources. For example, a
controller can signal information on which neighbor cells have reserved and are not
transmitting on a resource element that a serving cell is transmitting on. This
information can allow the terminal to configure an optimum receiver in the terminal.
The controller can also signal which neighbor cells are transmitting identically on a
resource element, that a serving cell is transmitting on. For example, transmitting
identically on a resource element can mean that the signals are transmitted such that
when the channel combines the signals from any two cells, the terminal cannot
distinguish the transmissions from the two cells when the channels are within a scale
factor of each other. This can use identical scrambling, spreading, interleaving, or the
like. The controller can signal the information above on the serving cell.
The method of this disclosure is preferably implemented on a programmed
processor. However, the controllers, flowcharts, and modules may also be
implemented on a general purpose or special purpose computer, a programmed
microprocessor or microcontroller and peripheral integrated circuit elements, an ASIC
or other integrated circuit, a hardware electronic or logic circuit such as a discrete
element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or
the like. In general, any device on which resides a finite state machine capable of
In step 720, the controller 140 can determine cells in which user equipment, such as
terminals 120, reside that desire a common multicast service and select at least one
serving cell 112 for transmitting the common multicast service. In step 730, the
controller 140 can send a signal to user equipment indicating the relationship between
cells with respect to serving cells 112 transmitting a common multicast transmission.
The signal can be a signal indicating which cells are serving cells 112 transmitting a
common multicast transmission and/or a signal indicating the identity of another cell,
such as an extended serving cell 114, which is transmitting on the same resource as
the serving cells. In step 740, the controller 140 can transmit at least a portion of the
common multicast transmission on the same resource on each serving cell 112. The
common multicast transmission can be determined from a single information stream,
such as from a media content server, for broadcast to multiple users at multiple
locations. The common multicast transmission can be transmitted on the serving cells
112 using the same physical layer attributes on each serving cell 112. The same
physical layer attributes can be the same resource element, as well as the same
spreading, the same channel coding, the same error detection coding (such as a cyclic
redundancy check on the payload data), the same time frequency resources, the same
frequency hopping pattern, and the like. In step 750, the controller 140 can transmit a
pilot signal on each serving cell 112, the pilot signal related to the at least a portion of
the common multicast transmission on each serving cell 112. The pilot transmitted on
each serving cell 112 can be a phase reference for the common multicast transmission
and can be the same signal transmitted on multiple serving cells 112. In step 760, the
controller 140 can transmit an interfering signal and a related pilot on at least one
different cell from the serving cells, such as an extended serving cell 114. In step 770,
the controller 140 can signal to a transmitting base station an indicator indicating not
to transmit on a resource on a non-serving cell, such as on an extended serving cell
114. In step 780, the controller 140 can signal to user equipment the identity of a cell,
such as an extended serving cell 114, which does not transmit on the same resource as
the serving cells. The same resource on each serving cell 112 can be the same slot,
the same frequency, the same period, the same Walsh codes, and the like on each
serving cell 112. In step 790, the flowchart 700 can end.
implementing the flowcharts shown in the Figures may be used to implement the
processor functions of this disclosure.
While this disclosure has been described with specific embodiments thereof, it
is evident that many alternatives, modifications, and variations will be apparent to
those skilled in the art. For example, various components of the embodiments may be
interchanged, added, or substituted in the other embodiments. Also, all of the
elements of each figure are not necessary for operation of the disclosed embodiments.
For example, one of ordinary skill in the art of the disclosed embodiments would be
enabled to make and use the teachings of the disclosure by simply employing the
elements of the independent claims. Accordingly, the preferred embodiments of the
disclosure as set forth herein are intended to be illustrative, not limiting. Various
changes may be made without departing from the spirit and scope of the disclosure.
AMENDED CLAIMS
received by the International Bureau on 30 March 2007 (30.03.2007)
1. A network controller comprising:
a processor configured to control the operations of the network
controller;
a serving cell signaling module coupled to the processor configured to
signal to user equipment a signal indicating the relationship between cells with respect
to serving cells transmitting a common multicast transmission; and
a network connection coupled to the processor the network connection
configured to send a signal for transmitting at least a portion of the common multicast
transmission on the same resource element on each serving cell, the network
connection configured to send a signal for transmitting a pilot signal on each serving
cell, the pilot signal related to the at least a portion of the common multicast
transmission on each serving cell, the network connection configured to send a signal
for transmitting an interfering signal and a related pilot on at least one different cell
from the serving cells.
2. The network controller according to claim 1, wherein the pilot
transmitted on at least one serving cell is a phase reference for the common multicast
transmission, and is the same signal transmitted on multiple serving cells.
3. The network controller according to claim 1, wherein the signal
Indicating the relationship between cells indicates which cells are serving cells
transmitting a common multicast transmission.
4. The network controller according to claim 1, wherein the signal
indicating the relationship between cells indicates the identity of a cell that is
transmitting on the same resource as the serving cells,
5. A wireless communication device comprising:
a controller configured to control the operations of the wireless device;
a receiver configured to receive information regarding serving cells
that are transmitting a common multicast transmission, the receiver also configured to
receive the common multicast transmission, at least a portion of which is transmitted
on the same resource on multiple serving cells, the receiver also configured to receive
a common broadcast pilot signal related to the common multicast transmission, the
common broadcast pilot signal being common to multiple cells; and
a multicast transmission decoder configured to decode the common
multicast transmission.
6. The wireless communication device according to claim 5, further
comprising a receiver characteristic adjustment module configured to adapt
characteristics of the receiver in response to receiving the information regarding the
serving cells.
7. The wireless communication device according to claim 6, further
comprising an antenna array coupled to the receiver,
wherein the receiver characteristic adjustment module is further
configured to adapt the antenna array in response to receiving the information
regarding the serving cells.
8. The wireless communication device according to claim 5, further
comprising a user interface configured to present the common multicast transmission
to a user of the wireless device.
9. A method in a wireless network, the method comprising;
signaling to user equipment a signal indicating the relationship
between at least one cell with respect to at least one serving cell transmitting a
common multicast transmission;
transmitting at least a portion of the common multicast transmission on
the same resource on the at least one serving cell; and
transmitting a pilot signal on the at least one serving cell, the pilot
signal related to the at least a portion of the common multicast transmission on the at
least one serving cell;
wherein a cell different from the at least one serving cell transmits an
interfering signal and a related pilot.
10. A method in a wireless device, the method comprising:
receiving information regarding serving cells that are transmitting a
common multicast transmission;
receiving the common multicast transmission, at least a portion of
which is transmitted on the same resource element on multiple serving cells;
receiving a common broadcast pilot signal related to the common
multicast transmission, the common broadcast pilot signal being common to multiple
cells; and
decoding the common multicast transmission.

A method and apparatus for neighbor assisted combining for localized multicast services. User equipment (120)
is sent a signal (730) indicating the relationship between cells with respect to serving cells (112) transmitting a common multicast
transmission. At least a portion of the common multicast transmission is transmitted (740) on the same resource on each serving
cell. A pilot signal is transmitted (750) on each serving cell, the pilot signal related to the at least a portion of the common multicast
transmission on each serving cell. An interfering signal and a related pilot are transmitted (760) on at least one different cell (114)
from the serving cells.

Documents:

01401-kolnp-2008-abstract.pdf

01401-kolnp-2008-claims.pdf

01401-kolnp-2008-correspondence others.pdf

01401-kolnp-2008-description complete.pdf

01401-kolnp-2008-drawings.pdf

01401-kolnp-2008-form 1.pdf

01401-kolnp-2008-form 3.pdf

01401-kolnp-2008-form 5.pdf

01401-kolnp-2008-gpa.pdf

01401-kolnp-2008-international publication.pdf

01401-kolnp-2008-international search report.pdf

01401-kolnp-2008-pct priority document notification.pdf

01401-kolnp-2008-pct request form.pdf

1401-KOLNP-2008-(03-10-2013)-CORRESPONDENCE.pdf

1401-KOLNP-2008-(03-10-2013)-OTHERS.pdf

1401-KOLNP-2008-(05-05-2014)-ABSTRACT.pdf

1401-KOLNP-2008-(05-05-2014)-ANNEXURE TO FORM 3.pdf

1401-KOLNP-2008-(05-05-2014)-CLAIMS.pdf

1401-KOLNP-2008-(05-05-2014)-CORRESPONDENCE.pdf

1401-KOLNP-2008-(05-05-2014)-DESCRIPTION (COMPLETE).pdf

1401-KOLNP-2008-(05-05-2014)-DRAWINGS.pdf

1401-KOLNP-2008-(05-05-2014)-FORM-2.pdf

1401-KOLNP-2008-(05-05-2014)-GPA.pdf

1401-KOLNP-2008-(05-05-2014)-OTHERS.pdf

1401-KOLNP-2008-(05-05-2014)-PETITION UNDER RULE 137.pdf

1401-KOLNP-2008-(07-05-2012)-ASSIGNMENT.pdf

1401-KOLNP-2008-(07-05-2012)-CORRESPONDENCE.pdf

1401-KOLNP-2008-(07-05-2012)-FORM-1.pdf

1401-KOLNP-2008-(07-05-2012)-FORM-2.pdf

1401-KOLNP-2008-(07-05-2012)-FORM-3.pdf

1401-KOLNP-2008-(07-05-2012)-FORM-5.pdf

1401-KOLNP-2008-(07-05-2012)-FORM-6.pdf

1401-KOLNP-2008-(07-05-2012)-PA-CERTIFIED COPIES.pdf

1401-KOLNP-2008-(12-09-2014)-AMANDED PAGES OF SPECIFICATION.pdf

1401-KOLNP-2008-(12-09-2014)-CORRESPONDENCE.pdf

1401-KOLNP-2008-(19-09-2014)-CORRESPONDENCE.pdf

1401-KOLNP-2008-ASSIGNMENT.pdf

1401-KOLNP-2008-CORRESPONDENCE 1.1.pdf

1401-kolnp-2008-form 18.pdf

abstract-1401-kolnp-2008.jpg

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Patent Number

264385

Indian Patent Application Number

1401/KOLNP/2008

PG Journal Number

52/2014

Publication Date

26-Dec-2014

Grant Date

24-Dec-2014

Date of Filing

07-Apr-2008

Name of Patentee

MOTOROLA, INC.

Applicant Address

1303 EAST ALGONQUIN ROAD SCHAUMBURG, ILLINOIS

Inventors:

#	Inventor's Name	Inventor's Address
1	CAI ZHIJUN	6264 GLENVIEW DRIVE, N. RICHLAND HILLS, TEXAS 76180
2	HARRISON ROBERT M.	3208 WALKER PLACE, GRAPEVINE. TEXAS 76051
3	AHMED MANSOOR	5760 SANDSHELL CIRCLE EAST, FORT WORTH, TEXAS 76137

PCT International Classification Number

H04Q 7/38,H04L 12/56

PCT International Application Number

PCT/US2006/039660

PCT International Filing date

2006-10-10

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	11/248313	2005-10-12	U.S.A.