Title of Invention	METHOD AND APPARATUS FOR RESPONDING TO A SCANNING REQUEST
Abstract	A method for responding to a scanning request comprises these steps: A base station (BS) receives a mobile scanning request (MOB_SCN_REQ) from a mobile station (MS); the BS responds to the MOB_SCN_REQ message and sends a mobile scanning response (MOB_SCN_RSP) to the MS, where the MOB_SCN_RSP message comprises a base station identity (BS ID) sequence indication field that maps BS IDs carried in the MOB_SCN_REQ message. An apparatus for responding to a scanning request comprises a sequence indicating unit. The method and apparatus may improve the utilization of air interface resources.

Title of Invention

METHOD AND APPARATUS FOR RESPONDING TO A SCANNING REQUEST

Abstract

A method for responding to a scanning request comprises these steps: A base station (BS) receives a mobile scanning request (MOB_SCN_REQ) from a mobile station (MS); the BS responds to the MOB_SCN_REQ message and sends a mobile scanning response (MOB_SCN_RSP) to the MS, where the MOB_SCN_RSP message comprises a base station identity (BS ID) sequence indication field that maps BS IDs carried in the MOB_SCN_REQ message. An apparatus for responding to a scanning request comprises a sequence indicating unit. The method and apparatus may improve the utilization of air interface resources.

Full Text	Cross-Reference to Related Applications This application is a continuation of International Application No. PCT/CN2008/072297, filed on Sep 8, 2008, which claims the benefit of Chinese Patent Application No. 200710181372.9, filed on Oct 20, 2007, both of which are hereby incorporated by reference in their entireties. Field of the Invention The present invention relates to a wideband radio access technology, and in particular, to a method and apparatus for responding to a scanning request. Background of the Invention A worldwide interoperability for microwave access (WIMAX) system, also called an 802.16 wireless metropolitan area network (MAN), can cover data communication areas of 25 to 30 miles. The WIMAX technology is based on wideband radio standards among 802.16 series proposed by the Institute of Electrical and Electronics Engineers (IEEE). So far, the IEEE 802.16 series include seven standards: IEEE 802.16, IEEE 802.16a, IEEE 802.16c, IEEE 802.16d, IEEE 802.16e, IEEE 802.16f, and IEEE 802.16g. EEE 802.16, IEEE 802.16a, and IEEE 802.16d are fixed radio access air interface standards, while IEEE 802.16e is a mobile wideband radio access air interface standard. WIMAX uses IEEE 802.16e as the air interface protocol. IEEE 802.16e is compatible with earlier IEEE 802.16d. IEEE 802.16e and IEEE 802.16d are the same in physical layer implementation mode, and have the following difference: IEEE 802.16e has extended orthogonal frequency division multiple access (OFDMA) to meet different carrier bandwidth requirements. To support mobility, IEEE 802.16e introduces a lot of new features in the media access control layer (MAC). By introducing new technologies such as orthogonal frequency division multiplex (OFDM) and multiple input multiple output (MIMO), the radio access technology develops towards higher capacity, wider coverage and mobility for a wideband radio system. The radio access technology coexists with and supplements the 3G network technology. Thus, the IEEE 802.16e technology has been a hot topic in the industry since its emergence. Based on IEEE 802.16e, WIMAX proposes a new enhanced technology—IEEE 802.16m. Currently, IEEE 802.16m specifies the following requirements: Mobile objects at the speed of 350 kilometers per hour are supported; the maximum downlink data transmission rate should be over 350 Mbps; the uplink data transmission rate should not be smaller than 200 Mbps; the bandwidth ranges from 5 MHz, 10 MHz, 20 MHz to 40MHz; and a maximum of 4x4 MIMOs can be used. When a 20 MHz bandwidth is used and communications are based on time division duplex (TDD), IEEE 802.16m requires that the downlink data transmission rate should be 40 Mbps and the uplink data transmission rate should be over 12 Mbps. In addition, IEEE 802.16m requires that the link layer access duration and handover delay should be less than 10 ms and 20 ms. Furthermore, IEEE 802.16m should be compatible with IEEE 802.16e. The WIMAX system consists of base stations (BSs) and mobile stations (MSs). A BS communicates with an MS through electromagnetic waves transmitted and received by a radio transceiver. Each BS has a unique base station identity (BS ID), which is a 48-bit field. Each BS has its coverage, and may communicate with each BS in its coverage. Each BS sends a neighbor cell broadcast (MOBNBRADV) message to BSs and MSs in a certain area on a timed basis, and stores the MOBNBRADV message. The MSs receive and store the MOB_NBR_ADV message. The MOBNBRADV message comprises BS IDs of the BSs in a certain area, where the BS IDs are arranged in sequence in the MOBNBRADV message. Each BS may communicate with multiple MSs in its coverage at the same time. However, one MS can communicate with only one BS at the same time, and the BS is the serving BS of the MS. As the MS keeps moving, the MS may go through coverage areas of muhiple BSs. In this case, the serving BS of the MS may be changed. During the movement, the MS may use a different BS that meets communication quality requirements as its serving BS to continue its communications. This process is known as handover. To ensure the continuity of communications and reduces possible interruptions of communications due to the handover, the MS needs to detect the signal quality of each adjacent BS to determine a target BS for handover when maintaining normal communications with the current serving BS. This detection process is called scanning. In this way, the MS may be handed over to a new BS with better communication quality when handover is required. Thus, the scanning process is a key step to ensure smooth handover. FIG 1 shows a scanning process in the prior art. The scanning process message includes a mobile scanning response (MOBSCNRSP) and a mobile scanning request (MOBSCNREQ). A MOBSCN-RSP message shall be transmitted by the BS either unsolicitedly or in response to a MOBSCN-REQ message sent by an MS. By sending the MOB_SCN_RSP message, the BS notifies the MS receiving the MOBSCNRSP of the scanning start time, scanning type and BS ID of a BS to be scanned. Both the MOB_SCN_RSP message and the MOBSCNREQ message include BS ID information. By carrying the BS ID information in the MOB_SCN_RSP message, the BS notifies the MS receiving the MOB_SCN_RSP message of which BSs are to be scanned. By carrying the BS ID information in the MOB_SCN_REQ message, the MS notifies its serving BS of which BSs are to be scanned. The MOB_SCN_RSP message and the MOBSCNREQ message also carry a scanning type field. Each BS ID in the MOBSCNRSP message and the MOBSCNREQ message corresponds to a scanning type. In the prior art, the BS ID information in the MOBSCNRSP message and the MOBSCNREQ message is divided into two parts. The first part of BS ID information in the MOBSCNREQ message corresponds to the BS IDs included in an MOBNBRADV message sent by the serving BS of an MS that sends the MOBSCNREQ message, and the second part is the IDs of BSs that are unsolicitedly scanned by the MS but not included in the MOBNBRADV message. One part of the BS ID information in the MOBSCNRSP message corresponds to the BS IDs included in an MOB_NBR_ADV message of a BS that sends the MOBSCNRSP message, and the second part is full base station identities (Full BS IDs) sent by the BS, where each full BS ID is represented by 48 bits. Among the second part of BS IDs in the MOB_SCN_RSP message, some are sent by the BS to respond to the MOBSCNREQ message, and some are unsolicitedly scanned by the BS but not included in the MOBSCNREQ message. Among the BS IDs in the scanning message, the part included in the MOB_NBR_ADV is represented in BS Index mode in IEEE 802.16e. That is, each of the BS IDs is represented by its sequence in the MOBNBRADV message. The second part in the scanning message is represented in Full BS ID mode. The number of BS IDs in the MOBNBRADV message is usually smaller than 255. Thus, only 8 bits are needed in BS Index mode, while 48 bits are needed in Full BS ID mode. Compared with the Full BS ID mode, the BS Index mode saves 40 bits per BS requesting the scanning. IEEE802.16e uses the Full BS ID mode rather than the BS Index mode to represent the second part of the BS IDs because these BS IDs are not included in the MOB_NBR_ADV FIG 2 shows a format of an MOB_SCN_REQ message in the prior art. The MOB_SCN_REQ message is composed of fields, each of which is represented by a number or letter. The following describes each field. Field 1 is a management message type field of 8 bits. Field 2 is a scan duration field of 8 bits. Field 3 is an interleaving interval field of 8 bits. Field 4 is a scan iteration field of 8 bits. Field 5 is an N_Recommended_BS_Index field of 8 bits. This field indicates the number of BS IDs that the MS intends to scan and that are included in the MOBNBR-ADV message. Field 6 is a "Configuration change count for MOBNBR-ADV" field of 8 bits. Field 7 is a NeighborBSIndex field of 8 bits. This field indicates the sequence of a BS ID that the MS intends to scan in the MOB_NBR_ADV message. Field 8 is a reserved field of 1 bit. Field 9 is a scanning type field of 3 bits. This field indicates the scanning type of the BS ID information mapped by field 7. The scanning type comprises scanning type 0, scanning type 1, scanning type 2, and scanning type 3. Field 10 is an N_Recommended_BS_Full field of 8 bits. This field indicates the number of BSs that the MS intends to scan. Field 11 is a Recommend BS ID field of 48 bits. This field indicates BS IDs of the BSs that the MS intends to scan. Field 12 is a reserved field of 1 bit. Field 13 is a scanning type field of 3 bits. This field indicates the scanning types of the BS IDs mapped by field II. When the value of field 5 is 0, fields 6-9 and field A are nonexistent. Field A includes repeated contents of fields 7-9 in turn. The number of repetitions is equal to the value of field 5. Field B includes repeated contents of fields 11-13 in turn. The number of repetitions is equal to the value of field 10. Field C indicates one of other fields in the MOBSCNREQ message. FIG. 3 shows a format of an MOB_SCN_RSP message in the prior art. The format of the MOBSCNRSP message is represented in the same way as that shown in FIG. 2. Fields 1-14 are 14 fields that are represented by numbers and arranged in ascending order, while fields 15-18 are four fields that are represented by numbers and arranged in ascending order. The following describes each field shown in FIG. 3. Field 1 is a management message type field of 8 bits. Field 2 is a scan duration field of 8 bits. Field 3 is a report mode field of 2 bits. Field 4 is a reserved field of 6 bits. Field 5 is a report period field of 8 bits. Field 6 is a report metric field of 8 bits. Field 7 is a start frame field of 8 bits. Field 8 is an interleaving interval field of 8 bits. Field 9 is a scan iteration field of 8 bits. Field 10 is an N_Recommended_BS_Index field of 8 bits. This field indicates the number of BS IDs that the BS intends to scan and that are included in the MOBNBR-ADV message. Fields 11-14 correspond to fields 6-9 shown in FIG. 2 in terms of content and meaning. Field D between field 14 and field A is 24 bits long and is present only when the scanning type of field 14 is scanning type 2 or scanning type 3. Field A shown in FIG 3 includes repeated contents of fields 12-14 and field D in turn. The number of repetitions is equal to the value of field 11. Field D is located between field Hand field A. Field 15 is an N_Recommended_BS_Full field of 8 bits. This field indicates the number of BSs that the BS intends to scan and that are not included in the MOB_NBR_ADV message. Field 16 is a Recommended BS ID field of 48 bits. This field indicates the BS IDs that the MS intends to scan and that are not included in the MOBNBRADV message. Field 17 is a reserved field of 1 bit. Field 18 is a scanning type field of 3 bits. This field indicates the scanning types of the BS IDs in field 16. Field D between field 18 and field B is 24 bits long and is present only when the scanning type of field 18 is scanning type 2 or scanning type 3. Field B shown in FIG. 3 includes repeated contents of fields 16-18 and field D in turn. The number of repetitions is equal to the value of field 15. Field D is located between field 18 and field B. Field E indicates one of other fields in the MOBSCNRSP message. Summary of the Invention Embodiments of the present invention provide a method and apparatus for responding to a scanning request to further improve the utilization rate of air interface resources. A method for responding to a scanning request in an embodiment of the present invention comprises: receiving a mobile scanning request MOB_SCN_REQ from an MS; and responding to the MOBSCNREQ message, and sending a mobile scanning response MOB_SCN_RSP to the MS, where: the MOBSCNRSP message comprises a BS ID sequence indication field that maps the BS IDs carried in the MOB_SCN_REQ message. An apparatus for responding to a scanning request in an embodiment of the present invention includes: a receiving unit, adapted to receive an MOBSCNREQ message; a sequence indicating unit, adapted to map the BS IDs in the MOB_SCN_REQ message; and a sending unit, adapted to send the MOB_SCN_RSP message according to the mapping. According to the method provided in an embodiment of the present invention, a BS ID sequence indication field is set in the MOBSCNRSP message; and the BS ID sequence indication field is used to map the BS IDs carried in the MOBSCNREQ message. Thus, a BS ID may be mapped by using a field of less than 48 bits. Compared with the Full BS ID in the prior art, the method provided in an embodiment of the present invention can further improve the utilization rate of air interface resources. A sequence indicating unit is also set in the apparatus provided in an embodiment of the present invention, which also improves the utilization rate of air interface resources. Brief Description of the Drawings For better understanding of the technical solution provided in the embodiments of the present invention or in the prior art, the following describes the accompanying drawings that are used in the embodiments of the present invention or in the prior art. Obviously, the following drawings are some exemplary embodiments of the present invention only. Those skilled in the art may obtain other drawings based on the following drawings without creative work. FIG I shows a scanning process in the prior art; FIG. 2 shows a format of an MOBSCNREQ message in the prior art; FIG 3 shows a format of an MOB_SCN_RSP message in the prior art; FIG 4 shows a scanning process provided in a first embodiment of the present invention; FIG. 5 shows a format of an MOBSCNRSP message in BS Index mode provided in the first embodiment of the present invention; FIG 6 shows a process of setting the MOBSCNRSP message in FIG. 5; FIG. 7 shows a mapping relation between a BS Bitmap scanning type field and a BS Bitmap field provided in the first embodiment of the present invention; FIG. 8 shows multiple scanning processes initiated by an MS; FIG. 9 shows a structure of an apparatus provided in a fourth embodiment of the present invention; and FIG 10 is a structure of a system provided in a fiftii embodiment of the invention. Detailed Description of the Invention During tiie implementation of the present invention, the inventor discovers at least the following problems in the prior art: Because one part of the BS IDs in a scanning process message may correspond to the BS IDs in the MOBNBRADV message, this part of the BS IDs is represented in BS Index mode in the prior art. When the BS IDs are represented in BS Index mode, each BS needs 8 bits only; when the BS IDs are represented in Full BS ID mode, each BS needs 48 bit. Thus, if the first part of the BS IDs is represented in BS Index mode, the utilization rate of air interface resources is improved. However, the second part of the BS IDs is still represented in Full BS ID mode, which consumes high air interface resources. Because the air interface resources are valuable, how to improve the utilization rate of air interface resources is still an urgent problem to be solved for the wideband radio access system. The technical solution of the present invention is hereinafter described in detail with reference to the accompanying drawings. It is evident that the embodiments are only exemplary embodiments of the present invention and the present invention is not limited to such embodiments. Other embodiments that those skilled in the art obtain based on embodiments of the present invention without creative work also fall in the scope of protection of the present invention. For better understanding of the objective, technical solution and merits of the present invention, the present invention is hereinafter described in detail with reference to accompanying drawings and exemplary embodiments. First embodiment: After receiving an MOBSCNREQ message from the MS, the BS sends an MOBSCNRSP message to the MS, responding to the scanning request of the MS. Among the BS IDs in the MOBSCNRSP message, the first part corresponds to the BS IDs included in the MOBNBRADV message sent by the BS; the second part is sent by the BS to respond to the MOBNBRREQ message; the third part is the BS IDs that the BS intends to scan and that are not included in the MOBSCNREQ message. The second part of the BS IDs is already carried in the MOBSCNREQ message and is sequenced. For the second part of the BS IDs, the first embodiment optimizes the MOBSCNRSP message as follows: A BS ID sequence indication field is set to map the second part of the BS IDs. The BS ID sequence indication field may be set in BS Index mode or in BS Bitmap mode. In BS Index mode, the BS ID sequence indication field is set to a BS Index field; in BS Bitmap mode, the BS ID sequence indication field is set to a BS Bitmap field. The second part of the BS IDs sent by the BS to respond to the MOBSCNREQ message may be set in two modes. First, the BS responds to all BS IDs carried in the MOB_SCN_REQ message, where all the BS IDs include BS IDs mapped in Full BS ID mode and in other modes; second, the BS responds to the BS IDs that are mapped in Full BS ID mode and carried in the MOBSCNREQ message. The following describes the method provided in the first embodiment based on the first mode. FIG. 4 shows a scanning process in which the BS responds to an MOBSCNREQ message sent from the MS according to the method provided in the first embodiment of the present invention. Step 401: The MS sends to the BS an MOB_SCN_REQ message in which the carried BS IDs are arranged in sequence. For example, if the MOB_SCN_REQ message carries a total of three BS IDs, the BS IDs are arranged as follows: BS IDI, BS ID2, BS ID3. Step 402: After receiving the MOB_SCN_REQ message from the MS, the BS sends an MOB_SCN_RSP message to the MS, where the MOB_SCN_RSP message maps all the BS IDs carried in the MOBSCNREQ message in BS Bitmap mode or BS Index mode. The BS Index mode provided in the first embodiment is the same as that in the prior art except for the following difference: The sequence in BS Index mode provided in the first embodiment is the sequence of the BS IDs that are already carried in the MOBSCNREQ message. In BS Index mode, the BS IDs carried in the MOBSCNREQ message are mapped as follows by using the BS Index field: Each BS ID has an index to indicate the sequence, and is identified by the index. For example, if the index of a BS ID is 1 in the MOB_SCN_REQ message, I is used to identify the BS ID in the MOB_SCN_RSP message. In BS Index mode, the value of the BS Index field is set to the index to map the BS ID. In the first embodiment, only 8 bits are needed to map a BS ID in BS Index mode. In contrast, 48 bits are needed in Full BS ID mode in the prior art. In this embodiment, a BS Bitmap field is set in the MOBSCNRSP message to represent the second part of the BS IDs in the MOB_SCN_RSP message in BS Bitmap mode. The BS Bitmap field maps the BS ID. Preferably, the number of bits in the BS Bitmap field is equal to the total number of BS IDs in the MOBSCNREQ message. Each bit in the BS Bitmap is mapped to a BS ID among all the BS IDs. The sequence of bits in the BS Bitmap field is mapped to the sequence of all the BS IDs. For example, the first bit in the BS Bitmap field is mapped to the first BS ID among all the BS IDs. Each bit in the BS Bitmap field uses 0 or 1 to indicate whether to request to scan a BS represented by the BS ID that is mapped to the bit. For example, if a bit in the BS Bitmap field is set to 1 according to an agreement, the BS requests to scan a BS represented by the BS ID that is mapped to the bit. In practical applications, the number of bits in the BS Bitmap field may be smaller than the total number of BS IDs. In this case, a bit in the BS Bitmap field is mapped to multiple BS IDs among all the BS IDs. That is, when the MOBSCNRSP message has one or multiple BS IDs, the bit mapped to multiple BS IDs is set to an agreed value. The number of bits in the BS Bitmap field may also be greater than the total number of BS IDs. In this case, multiple bits in the BS Bitmap field are mapped to a BS ID among all the BS IDs. When the number of bits in the BS Bitmap field is smaller or greater than the total number of BS IDs, the BS Bitmap field may be used with reference to the scenario where the number of bits in the BS Bitmap field is equal to the total number of BS IDs in the MOBSCNREQ message. A reserved bit may also be set in the BS Bitmap field, which is not used to map all the BS IDs. To map the BS IDs, the BS Bitmap field may map all the BS IDs or part of the BS IDs that the MS requests to scan. For the specific mapping method in these two modes, refer to related descriptions of embodiments of the present invention. For the mapping between the BS index field and the BS IDs, refer to related descriptions of the mapping between the BS Bitmap field and the BS IDs. Compared with the Full BS ID mode in the prior art in which 48 bits are needed, only one bit is needed to map a BS ID in BS Bitmap mode. In the preceding first mode, the index in BS Index mode is the index of the BS ID among all the BS IDs. When the BS Index mode is used in the second mode, the index of a BS ID is the index of the Full BS ID among all the BS IDs mapped in Full BS ID mode in an MOB_SCN_REQ message. Preferably, when the BS Bitmap mode is used, the number of bits in the BS Bitmap field is equal to the number of BS IDs mapped in Full BS ID mode in the MOBSCNREQ message. In the preceding second mode, the BS Index mode and the BS Bitmap mode may be used with reference to the first mode, and will not be further described. Preferably, a carrying indication field is set in a current MOBSCNRSP message to indicate whether the MOB_SCN_RSP message comprises BS IDs that are already carried in an MOBSCNREQ message. This indication field may use one of six bits reserved in the current MOB_SCN_RSP message, one of other fields in the current MOBSCNRSP message or a new field with a variable length. The carrying indication field is optional. Without the carrying indication field, the MOBSCNRSP message may also use the BS Bitmap mode or BS Index mode directly. FIG 5 shows a format of an MOBSCNRSP message in BS Index mode. Compared with FIG. 3, FIG. 5 has the following differences: An MSR Ind field is inserted between field 3 and field 4; fields 19-22, field D and field F are inserted between field B and field E. The following describes each field shown in FIG. 5. Fields 1-3, fields 4-14, field A, field D between field 14 and field A, and field E shown in FIG. 5 are the same as those fields with the same labels and relative positions shown in FIG 3 in terms of contents and meanings. Compared with the fields with the same labels and relative positions shown in FIG. 3, fields 15-18, field B and field D between field B and field 18 shown in FIG. 5 have only the following difference: The BS IDs in those fields shown in FIG. 5 are BS IDs that a BS intends to scan, that is, the third part of BS IDs. In FIG. 5, field 19 is used to map the number of BS IDs that are already carried in the MOB_SCN_REQ message and should be carried in the MOBSCNRSP message, that is, the number of the second part of BS IDs. Field 19 is 8 bits long; field 20 is an index of the BS ID in the MOBSCNREQ message and is 8 bits long; field 21 is a reserved field of 1 bit; field 22 indicates a scanning type of the BS ID mapped in field 20; field D between field 22 and field F is 24 bits long and is present only when the scanning type is scanning type 2 or scanning type 3; field F is used to repeat the contents in fields 19-22 and field D, and the number of repetitions is equal to the value of field 19. The MSR Ind field is the carrying indication field, which is used to indicate whether the MOBSCNRSP message comprises BS IDs that are already carried in the MOBSCNREQ message. For example, when the value of the MSR Ind field is agreed to be 1, the MOBSCNRSP message comprises BS IDs that are already carried in the MOBSCNREQ message. If the value of the MSR Ind field is agreed to be 1, fields 19-22, field F, and field D between field F and field 22 are present; otherwise these fields are nonexistent. FIG 6 shows a process of setting the format of an MOBSCNRSP message. Step 601: Set fields 1-3, the MSR Ind field, and fields 4-6. Step 602: Judge whether the value of field 2 is a non-zero value; if so, proceed to step 603; otherwise, go to step 610. Step 603: Set fields 7-10. Step 604: Judge whether the value of field 10 is a non-zero value; if so, proceed to step 605; otherwise, go to step 606. Step 605: Set fields 11-14, field A, and field D between field A and field 14. Step 606: Set fields 15-18, field B, and field D between field B and field 18. Step 607: Judge whether the value of the MSR Ind field is 1; if so, proceed to step 608; otherwise, go to step 609. Step 608: Set fields 19-22, field F, and field D between field F and field 22. Step 609: Set field E. Step 610: The setting process ends. For the method for setting each field shown in FIG 6, refer to related descriptions of embodiments of the present invention, and the method will not be further described. In FIG. 5 and FIG. 6, the carrying indication field MSR Ind may use one of six bits reserved in the MOB_SCN_RSP message. In practical applications, the MSR Ind field may use one or multiple bits among other bits or a new field with a variable length in the MOBSCNRSP message. When the second part of the BS IDs in the MOB_SCN_RSP message is represented in BS Bitmap mode, the diflference between the format of the MOBSCNRSP message and that shown in FIG. 5 is as follows: Fields 19-22 shown in FIG 5 are replaced with the BS Bitmap field; field D between field F and field 22 shown in FIG. 5 is replaced witii the BS Bitmap scanning type field; and field F is present only when the BS Bitmap scanning type field comprises scanning type 2 or scanning type 3. For the method for setting the BS Bitmap field, refer to related descriptions of embodiments of the present invention. Bits in the BS Bitmap scanning type field indicate a scanning type. Starting from the initial bit of the scanning field, every 3 bits indicate a scanning type. The sequence of scanning types corresponds to the values and sequences of bits in the BS Bitmap field. This is described in detail with reference to FIG. 7. The BS Bitmap field in FIG. 7 is 5 bits long, and indicates that the number of BS IDs carried in the MOBSCNREQ message is 5. The first bit in FIG. 7 corresponds to the first BS ID in the MOBSCNREQ message, and the rest of bits correspond to the rest of BS IDs in the MOBSCNREQ message in turn. In FIG 7, when the value of a bit is 1, the BS requests to scan a BS represented by a BS ID that is mapped to the bit, and the bit corresponds to a 3-bit scanning type field. Scanning types that correspond to each bit whose value is 1 in the BS Bitmap field are arranged in the sequence of the bits. As shown in FIG 7, the values of the second bit and the fourth bit in the BS Bitmap field are I. Thus, the scanning type that corresponds to the second bit is represented by the first 3 bits in the BS Bitmap scanning type field, while the scanning type that corresponds to the fourth bit is represented by the second 3 bits in the BS Bitmap scanning type field. In the BS Bitmap scanning type field shown in FIG. 7, 0, 1 and 2 indicate that the bit is bit 0, bit 1 and bit 2 in the 3 bits. If the second part of BS IDs in the MOBSCNRSP message uses the BS Bitmap mode, the process of setting the MOBSCNRSP message is similar to that shown in FIG 6 except that step 608 is changed as follows: Set the BS Bitmap field, BS Bitmap scanning type field and field F. In this embodiment, the MOBSCNRSP message is optimized. For BS IDs that are already carried in the MOBSCNREQ message, the BS Index mode or BS Bitmap mode is used in the MOBSCNRSP message to map the BS IDs. In BS Index mode, only 8 bits are needed to map each BS ID; in BS Bitmap mode, at least one bit is needed to map each BS ID. In current Full BS ID mode, 48 bits are needed to map each BS ID. Thus, the method provided in this embodiment of the present invention may greatly improve the utilization rate of air interface resources. Second embodiment: A message ID field is set in a scanning process message to identify each scanning process message, so that the MOB_SCN_REQ matches the MOBSCNRSP message. When multiple scanning processes are available at a time, the message ID field may specify which MOBSCNREQ message matches an MOBSCNRSP message. Thus, the message ID field may be used to match the MOB_SCN_REQ message with the MOBSCNRSP message. The message ID field may be named "Configuration change count for MOBSCNREQ", "Transaction ID" or "Sequence Number". The length of the message ID field may be 1-32 bits or more. The message ID field may be a new field with a variable length, an existing field, or one or multiple bits of an existing field in the scanning process message. The following gives an example to describe how to use the message ID field. Supposing the message ID field is 2 bits long, the message ID field may match four pairs of scanning process messages because 2 bits may represent four numbers, that is, 0-3. The specific matching method is as follows: A message ID field is set in an MOBSCNREQ message and an MOBSCNRSP message; when the value of the message ID field in the MOBSCNRSP message is the same as that in the MOBSCNREQ message, the MOBSCNRSP message matches the MOBSCNREQ message. For example, when an MS sends an MOBSCNREQ message, the MS sets the ID field in the MOBSCNREQ message to 1; after a BS receives the MOB_SCN_REQ message, the BS sends an MOB_SCN_RSP message, and also sets the message ID field in the MOB_SCN_RSP message to 1, which specifies that the MOBSCNRSP message matches the MOB_SCN_REQ message with the ID 1. A message ID field is added to a scanning process message to specify which MOBSCNREQ message matches an MOBSCNRSP message. In this case, errors may be avoided when the method provided in the first embodiment of the present invention is used to scan. The reasons are as follows: If the message ID field is not included in the scanning process message, the MOBSCNRSP message matches a latest MOBSCNREQ message that the MS sends according to the prior art; however, after the MS sends an MOBSCNREQ message actively, a BS does not receive the message due to transmission errors; in this case, the BS sends an MOBSCNRSP message to the MS actively, but the MS cannot judge whether the MOBSCNRSP matches the MOBSCNREQ message or is sent by the BS actively. In this embodiment, the preceding errors are avoided because a message ID field is used to match the scanning process messages. After a message ID field is added to the scanning process messages, the preceding errors are avoided and multiple scanning processes may be initiated by the MS or BS. The following describes this embodiment in detail, supposing the MS initiates multiple scanning processes. FIG. 8 shows multiple scanning processes initiated by an MS after a message ID field is added. As shown in FIG. 8, the MS sends two MOBSCNREQ messages to a BS. The message ID field is set to 1 in one MOBSCNREQ message and to 2 in the other MOB_SCN_REQ message. The BS sends two MOBSCNRSP messages. The message ID field is set to 1 in one MOBSCNREQ message and to 2 in the other MOB_SCN_REQ message. After receiving the MOBSCNRSP messages, the MS may know that the MOB_SCN_RSP message with the message ID field 2 matches the MOB_SCN_REQ message with the message ID field 2, and that the MOB_SCN_RSP message with the message ID field 1 matches the MOBSCNREQ message with the message ID field 1. Thus, when an MS sends multiple MOBSCNREQ messages, the MS may judge which MOBSCNREQ message matches an MOBSCNRSP message according to the message ID field. The initiating of multiple scanning processes by the MS may be: initiating multiple scanning processes by the MS at the same time, or initiating multiple scanning processes in sequence by the MS. Third embodiment: A mode indication field is further set in a scanning process message to indicate whether the scanning process message uses the BS Bitmap mode or BS Index mode. The mode indication filed is used to indicate which mode a current scanning process message uses. Subsequent scanning process messages will use the mode indicated by the mode indication field. It should be noted that a message may use either the BS Index mode or the BS Bitmap mode only. The message can select a proper mode according to the actual situation. The mode indication field may be a format indication bit (FMT bit), a field including multiple bits, or a bit in the mode indicafion field. Fourth embodiment: This embodiment provides an apparatus for responding to a scanning request. The apparatus comprises a receiving unit, a sending unit, and a sequence indicating unit, where: the receiving unit is adapted to receive an MOB_SCN_REQ message; the sending unit is adapted to send an MOBSCNRSP message; and the sequence indicating unit is adapted to map an information unit in the receiving unit. Preferably, the apparatus further comprises an information unit, which is adapted to store BS IDs in the MOB_SCN_REQ message received by the receiving unit. The information unit may further include a mode indication unit, which is adapted to indicate a structure of the sequence indicating unit. The information unit may further include a carrying indication unit, which is adapted to indicate whether the receiving unit includes the information unit. The sequence Indicating unit in this embodiment may be a BS Index unit or a BS Bitmap unit. The BS Bitmap unit comprises a subunit, whicii is adapted to map tiie information unit. The location of the subunit corresponds to the sequence of the BS ID in the MOBSCNREQ message. The subunit is set to indicate whether the scanning message comprises the BS ID of the sequence. The number of subunits may be equal to the number of information units or number of Full BS IDs in the information unit. The apparatus provided in this embodiment further comprises a reception/transmission identifying unit, which is adapted to match the MOBSCNRSP message sent by the sending unit with the MOBSCNREQ message received by the receiving unit. The following further describes the apparatus provided in this embodiment with reference to FIG. 9. As shown in FIG. 9, 900 represents the apparatus; 910 represents the receiving unit; 920 represents the carrying indication unit; 930 represents the sequence indicating unit; 940 represents the sending unit; 950 represents the mode indication unit; 911 represents the reception/transmission identifying unit in the receiving unit; 912 represents the information unit; 931 represents the BS Bitmap unit; and 932 represents the BS Index unit. The information unit comprises a carrying indication unit and a mode indication unit, and the sequence indicating unit comprises a BS Bitmap unit and a BS Index unit. The receiving unit 910 receives an MOBSCNREQ message, and stores the BS ID in the MOBSCNREQ message in the information unit 912; the reception/transmission identifying unit 911 in the receiving unit stores the message ID field in the MOB_SCN_REQ message. The carrying indication unit 920 receives a message from the receiving unit 910 and judges whether the information unit 912 exists; if so, the carrying indication unit 920 sends carrying indication information to the sequence indicating unit 930; after receiving the carrying indication information, the sequence indicating unit 930 receives the message from the receiving unit 910; the sequence indicating unit 930 is adapted to: map BS IDs in the information unit 912, obtain BS ID sequence indication information after tiie mapping, and send the BS ID sequence indication information to the sending unit 940. The sending unit 940 receives the BS ID sequence indication information, and sets the message ID field in the reception/transmission identifying unit 941 of the sending unit to a value that the is same as or corresponds to the value of the message ID field in the reception/transmission identifying unit 911 of the receiving unit. Then, the sending unit 940 sends an MOB_SCN_RSP message externally, where the MOB_SCN_RSP message carries the BS ID sequence indication information and the message ID field. The sequence indicating unit 930 may use the structure of the BS Bitmap unit 931 or BS Index unit 932. The mode indication unit 950 sends mode indication information to the sequence indicating unit 930 to indicate whether the sequence indicating unit 930 uses the structure of the BS Bitmap unit 931 or the BS Index unit 932. It should be noted that only the BS Bitmap unit 931 or the BS Index unit 932 is available. In practical applications, there may be one or multiple information units 912. When there are multiple information units 912, each of the information units is arranged in a sequence same as that of BS IDs in the MOBSCNREQ message. The BS Bitmap unit 931 comprises a subunit, which is not illustrated in FIG 9. The location of the subunit corresponds to the location of the information unit 912. The subunit is set to indicate whether the MOB_SCN_RSP message comprises contents of the information unit. The BS Index unit 932 is set according to the location of an information unit among all the information units 912 that stores BS IDs that the apparatus 900 wants to carry in the MOBSCNRSP message. The number of BS Index units 932 is equal to the number of BS IDs that the apparatus 900 wants to carry in the MOB_SCN_REQ message and that are also included in the MOBSCNREQ message. In FIG. 9, the units 920, 950, 911 and 941 are optional units. Fifth embodiment: This embodiment provides a system for responding to a scanning request. The system provided in this embodiment includes an MS, a BS, and a sequence indicating unit, where: the MS is adapted to send an MOBSCNREQ message; the BS is adapted to receive the MOBSCNREQ message and send an MOBSCNRSP message; and the sequence indicating unit is located in the BS and adapted to map the information unit in the MOBSCNREQ message. Preferably, the system further comprises a mode indication unit, which is located in the BS and adapted to indicate the structure of the sequence indicating unit. Preferably, the system further comprises a carrying indication unit, which is located in the BS and adapted to indicate whether the BS comprises the information unit. Preferably, the system further comprises a reception/transmission identifying unit, which is located in the MS and BS and adapted to match the MOB_SCN_RSP message with the MOB_SCN_REQ message. The following further describes the system provided in this embodiment with reference to FIG. 10. In FIG. 10, 1000 represents the BS; 1001 represents the MS; 1060 represents the sending unit of the MS; 1061 represents the reception/transmission identifying unit in the sending unit 1060 of the MS; 1070 represents the receiving unit of the MS; 1071 represents the reception/transmission identifying unit in the receiving unit 1070 of the MS; 1010 represents the receiving unit of the BS; 1011 represents the reception/transmission identifying unit in the receiving unit 1010 of the BS; 1012 represents the information unit; 1020 represents the carrying indication unit; 1030 represents the sequence indicating unit; 1031 represents the BS Bitmap unit; and 1032 represents the BS Index unit; 1040 represents the sending unit of the BS; 1041 represents the reception/transmission identifying unit in the sending unit 1040 of the BS; and 1050 represents the mode indication unit. The internal structure of the BS 1000 shown in FIG. 10 corresponds to that of the apparatus 900 shown in FIG. 9 according to the last two digits of the numbers in the drawings and so is the mapping relation between the units. That is, the last two digits of the BS 1000 are the same as those of the apparatus 900 in the drawings, and so are the internal structures of the units represented by the numbers in the drawings and mapping relation between the units. In FIG. 10, the sending unit 1060 of the MS 1001 sends an MOBSCNREQ message to the receiving unit 1010 of the BS 1000, where the MOBSCNREQ message carries a message ID field generated by the reception/transmission identifying unit 1061; the receiving unit 1070 of the MS 1001 receives an MOB_SCN_RSP message from the sending unit 1040 of the BS 1000, and stores a message ID field carried in the MOB_SCN_RSP message in the reception/transmission identifying unit 1071; the reception/transmission identifying unit 1071 receives the message ID field from the reception/transmission identifying unit 1061, and judges whether the message ID field carried in the MOBSCNRSP message is the same as or corresponds to the message ID field sent from the reception/transmission identifying unit 1061; if so, the MOBSCNRSP message matches the MOB_SCN_REQ message; otherwise, the MOBSCNRSP message does not match the MOBSCNREQ message. In FIG. 10, the units 1020, 1050, lOIl, I04I, 1061 and 1071 are optional units. For the sequence indicating unit, BS Bitmap unit, BS Index unit, mode indication unit, carrying indication unit, reception/transmission identifying unit and other units in the apparatus provided in the fourth embodiment and system provided in the fifth embodiment, the internal structures are set according to the method provided in an embodiment of the present invention, and will not be further described. According to the preceding solution, an MOBSCNRSP message is optimized. For BS IDs that are already carried in an MOB_SCN_REQ message, the MOB_SCN_RSP message provided in embodiments of the present invention is represented in BS Index mode or BS Bitmap mode. The sequences used in BS Index mode and BS Bitmap mode are sequences of the BS IDs in the MOBSCNREQ message. When the MOBSCNRSP message is represented in BS Index mode or BS Bitmap mode, each of BS IDs that are already carried in the MOBSCNREQ message is represented by 8 bits or 1 bit only. In contrast, 48 bits are needed in Full BS ID mode in the prior art. Thus, the method provided in embodiments of the present invention can greatly improve the utilization of air interface resources. In embodiments of the present invention, a message ID field is further set to match the MOB_SCN_RSP message with the MOB_SCN_REQ message, so that the MS or BS can initiate multiple scanning processes without errors during the matching between the MOBSCNRSP message and the MOB_SCN_REQ message. In embodiments of the present invention, a mode indication mode is further set to indicate whether a current scanning process message uses the BS Bitmap mode or BS Index mode, which can achieve the compatibility between the BS Bitmap mode and the BS Index mode. Thus, different modes may be selected according to different scenarios, and the utilization of air interface resources may be maximized. Through the preceding description of embodiments of the present invention, it is understandable to those skilled in the art that embodiments of the present invention may be implemented by hardware or by software in combination with a necessary hardware platform. Thus, the technical solution of the present invention may be made into software. The software may be stored in a non-volatile storage medium (for example, a CD-ROM, a USB disk, or a mobile hard disk), and include several instructions that instruct a computer device (a personal computer, a server, or a network device) to execute the method provided in each embodiment of the present invention. Although the present invention has been described through several exemplary embodiments, the invention is not limited to such embodiments. It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. The invention is intended to cover the modifications and variations provided that they fall in the scope of protection defined by the following claims or their equivalents. WE CLAIM: 1. A method for responding to a scanning request, comprising: receiving a mobile scan request MOBSCNREQ message sent by a mobile station ( MS ) ; and responding to the MOBSCNREQ message by sending a mobile scanning response message MOBSCNRSP to the MS, wherein the MOBSCNRSP message comprises a base station ( BS ) ID sequence indication field which maps the BS IDs carried in the MOB_SCN_REQ message. 2. The method for responding to a scanning request according to claim 1, wherein the MOB_SCN_RSP message further comprises a carrying indication field, adapted to indicate whether the BS IDs in the MOBSCNREQ message are carried in the MOB_SCN_RSP message. 3. The method for responding to a scanning request according to claim I, wherein the MOBSCNRSP message further comprises a mode indication field, adapted to indicate how the BS ID sequence indication filed is set. 4. The method for responding to a scanning request according to claim 1, wherein the BS ID sequence indication field is set as a BS Index field and the BS Index field maps the BS IDs carried in the MOBSCNREQ message. 5. The method for responding to a scanning request according to claim 1, wherein the BS ID sequence indication field is set as a BS Bitmap field and the BS Bitmap field maps the BS IDs carried in the MOBSCNREQ message. 6. The method for responding to a scanning request according to claim 5, wherein the process the BS Bitmap field maps the BS IDs carried in the MOBSCNREQ message comprises: the position of each bit in the BS Bitmap field maps a BS ID in the corresponding position of the BS IDs; and the value of each bit in the BS Bitmap field indicates whether the corresponding BS ID is carried in the MOBSCNRSP message. 7. The method for responding to a scanning request according to claim 6, wherein the number of bits in the BS Bitmap field is set as the number of BS IDs. 8. The method for responding to a scanning request according to claim 6, wherein the number of bits in the BS Bitmap field is set as the number of Full BS ID in the BS IDs. 9. The method for responding to a scanning request according to any one of claims 1 -8, wherein a message ID field is set in the MOBSCNREQ message and the MOB_SCN_RSP message. 10. An apparatus for responding to a scanning request, comprising: a receiving unit, adapted to receive an MOBSCNREQ message; a sequence indicating unit, adapted to map the BS IDs in the MOBSCNREQ message; and a sending unit, adapted to send an MOBSCNRSP message according to the mapping. 11. The apparatus for responding to a scanning request according to claim 10, further comprising: an information unit, adapted to store BS IDs in the MOBSCNREQ message received by the receiving unit. 12. The apparatus for responding to a scanning request according to claim 11, wherein the information unit further comprises: a mode indication unit, adapted to send mode indication information to the sequence indicating unit; and the sequence indicating unit, adapted to judge the structure of the sequence indicating unit according to the mode indication message. 13. The apparatus for responding to a scanning request according to claim 11, wherein the information unit further comprises: a carrying indication unit, adapted to acquire the number of BS IDs and send carrying indication information to the sequence indicating unit according to the number. 14. The apparatus for responding to a scanning request according to claim 10, wherein the sequence indicating unit further comprises: a BS Index unit, adapted to map BS IDs by BS Index. 15. The apparatus for responding to a scanning request according to claim 10, wherein the sequence indicating unit further comprises: a BS Bitmap unit, adapted to map BS IDs by BS Bitmap. Dated this 29* day of December 2009 A method for responding to a scanning request comprises these steps: A base station (BS) receives a mobile scanning request (MOB_SCN_REQ) from a mobile station (MS); the BS responds to the MOB_SCN_REQ message and sends a mobile scanning response (MOB_SCN_RSP) to the MS, where the MOB_SCN_RSP message comprises a base station identity (BS ID) sequence indication field that maps BS IDs carried in the MOB_SCN_REQ message. An apparatus for responding to a scanning request comprises a sequence indicating unit. The method and apparatus may improve the utilization of air interface resources.

Full Text

Cross-Reference to Related Applications
This application is a continuation of International Application No.
PCT/CN2008/072297, filed on Sep 8, 2008, which claims the benefit of Chinese Patent
Application No. 200710181372.9, filed on Oct 20, 2007, both of which are hereby
incorporated by reference in their entireties.
Field of the Invention
The present invention relates to a wideband radio access technology, and in
particular, to a method and apparatus for responding to a scanning request.
Background of the Invention
A worldwide interoperability for microwave access (WIMAX) system, also called
an 802.16 wireless metropolitan area network (MAN), can cover data communication
areas of 25 to 30 miles.
The WIMAX technology is based on wideband radio standards among 802.16
series proposed by the Institute of Electrical and Electronics Engineers (IEEE). So far, the
IEEE 802.16 series include seven standards: IEEE 802.16, IEEE 802.16a, IEEE 802.16c,
IEEE 802.16d, IEEE 802.16e, IEEE 802.16f, and IEEE 802.16g. EEE 802.16, IEEE
802.16a, and IEEE 802.16d are fixed radio access air interface standards, while IEEE
802.16e is a mobile wideband radio access air interface standard. WIMAX uses IEEE
802.16e as the air interface protocol.
IEEE 802.16e is compatible with earlier IEEE 802.16d. IEEE 802.16e and IEEE
802.16d are the same in physical layer implementation mode, and have the following
difference: IEEE 802.16e has extended orthogonal frequency division multiple access
(OFDMA) to meet different carrier bandwidth requirements. To support mobility, IEEE
802.16e introduces a lot of new features in the media access control layer (MAC). By

introducing new technologies such as orthogonal frequency division multiplex (OFDM)
and multiple input multiple output (MIMO), the radio access technology develops towards
higher capacity, wider coverage and mobility for a wideband radio system. The radio
access technology coexists with and supplements the 3G network technology. Thus, the
IEEE 802.16e technology has been a hot topic in the industry since its emergence.
Based on IEEE 802.16e, WIMAX proposes a new enhanced technology—IEEE
802.16m. Currently, IEEE 802.16m specifies the following requirements: Mobile objects
at the speed of 350 kilometers per hour are supported; the maximum downlink data
transmission rate should be over 350 Mbps; the uplink data transmission rate should not be
smaller than 200 Mbps; the bandwidth ranges from 5 MHz, 10 MHz, 20 MHz to 40MHz;
and a maximum of 4x4 MIMOs can be used. When a 20 MHz bandwidth is used and
communications are based on time division duplex (TDD), IEEE 802.16m requires that
the downlink data transmission rate should be 40 Mbps and the uplink data transmission
rate should be over 12 Mbps. In addition, IEEE 802.16m requires that the link layer access
duration and handover delay should be less than 10 ms and 20 ms. Furthermore, IEEE
802.16m should be compatible with IEEE 802.16e.
The WIMAX system consists of base stations (BSs) and mobile stations (MSs). A
BS communicates with an MS through electromagnetic waves transmitted and received by
a radio transceiver. Each BS has a unique base station identity (BS ID), which is a 48-bit
field. Each BS has its coverage, and may communicate with each BS in its coverage. Each
BS sends a neighbor cell broadcast (MOBNBRADV) message to BSs and MSs in a
certain area on a timed basis, and stores the MOBNBRADV message. The MSs receive
and store the MOB_NBR_ADV message. The MOBNBRADV message comprises BS
IDs of the BSs in a certain area, where the BS IDs are arranged in sequence in the
MOBNBRADV message. Each BS may communicate with multiple MSs in its
coverage at the same time. However, one MS can communicate with only one BS at the
same time, and the BS is the serving BS of the MS. As the MS keeps moving, the MS may

go through coverage areas of muhiple BSs. In this case, the serving BS of the MS may be
changed. During the movement, the MS may use a different BS that meets communication
quality requirements as its serving BS to continue its communications. This process is
known as handover. To ensure the continuity of communications and reduces possible
interruptions of communications due to the handover, the MS needs to detect the signal
quality of each adjacent BS to determine a target BS for handover when maintaining
normal communications with the current serving BS. This detection process is called
scanning. In this way, the MS may be handed over to a new BS with better communication
quality when handover is required. Thus, the scanning process is a key step to ensure
smooth handover.
FIG 1 shows a scanning process in the prior art. The scanning process message
includes a mobile scanning response (MOBSCNRSP) and a mobile scanning request
(MOBSCNREQ). A MOBSCN-RSP message shall be transmitted by the BS either
unsolicitedly or in response to a MOBSCN-REQ message sent by an MS. By sending the
MOB_SCN_RSP message, the BS notifies the MS receiving the MOBSCNRSP of the
scanning start time, scanning type and BS ID of a BS to be scanned.
Both the MOB_SCN_RSP message and the MOBSCNREQ message include BS
ID information. By carrying the BS ID information in the MOB_SCN_RSP message, the
BS notifies the MS receiving the MOB_SCN_RSP message of which BSs are to be
scanned. By carrying the BS ID information in the MOB_SCN_REQ message, the MS
notifies its serving BS of which BSs are to be scanned. The MOB_SCN_RSP message and
the MOBSCNREQ message also carry a scanning type field. Each BS ID in the
MOBSCNRSP message and the MOBSCNREQ message corresponds to a scanning
type.
In the prior art, the BS ID information in the MOBSCNRSP message and the
MOBSCNREQ message is divided into two parts. The first part of BS ID information in
the MOBSCNREQ message corresponds to the BS IDs included in an

MOBNBRADV message sent by the serving BS of an MS that sends the
MOBSCNREQ message, and the second part is the IDs of BSs that are unsolicitedly
scanned by the MS but not included in the MOBNBRADV message. One part of the BS
ID information in the MOBSCNRSP message corresponds to the BS IDs included in an
MOB_NBR_ADV message of a BS that sends the MOBSCNRSP message, and the
second part is full base station identities (Full BS IDs) sent by the BS, where each full BS
ID is represented by 48 bits. Among the second part of BS IDs in the MOB_SCN_RSP
message, some are sent by the BS to respond to the MOBSCNREQ message, and some
are unsolicitedly scanned by the BS but not included in the MOBSCNREQ message.
Among the BS IDs in the scanning message, the part included in the
MOB_NBR_ADV is represented in BS Index mode in IEEE 802.16e. That is, each of the
BS IDs is represented by its sequence in the MOBNBRADV message. The second part
in the scanning message is represented in Full BS ID mode.
The number of BS IDs in the MOBNBRADV message is usually smaller than
255. Thus, only 8 bits are needed in BS Index mode, while 48 bits are needed in Full BS
ID mode. Compared with the Full BS ID mode, the BS Index mode saves 40 bits per BS
requesting the scanning.
IEEE802.16e uses the Full BS ID mode rather than the BS Index mode to represent
the second part of the BS IDs because these BS IDs are not included in the
MOB_NBR_ADV
FIG 2 shows a format of an MOB_SCN_REQ message in the prior art.
The MOB_SCN_REQ message is composed of fields, each of which is represented
by a number or letter. The following describes each field.
Field 1 is a management message type field of 8 bits.
Field 2 is a scan duration field of 8 bits.
Field 3 is an interleaving interval field of 8 bits.
Field 4 is a scan iteration field of 8 bits.

Field 5 is an N_Recommended_BS_Index field of 8 bits. This field indicates the
number of BS IDs that the MS intends to scan and that are included in the
MOBNBR-ADV message.
Field 6 is a "Configuration change count for MOBNBR-ADV" field of 8 bits.
Field 7 is a NeighborBSIndex field of 8 bits. This field indicates the sequence of
a BS ID that the MS intends to scan in the MOB_NBR_ADV message.
Field 8 is a reserved field of 1 bit.
Field 9 is a scanning type field of 3 bits. This field indicates the scanning type of
the BS ID information mapped by field 7. The scanning type comprises scanning type 0,
scanning type 1, scanning type 2, and scanning type 3.
Field 10 is an N_Recommended_BS_Full field of 8 bits. This field indicates the
number of BSs that the MS intends to scan.
Field 11 is a Recommend BS ID field of 48 bits. This field indicates BS IDs of the
BSs that the MS intends to scan.
Field 12 is a reserved field of 1 bit.
Field 13 is a scanning type field of 3 bits. This field indicates the scanning types of
the BS IDs mapped by field II.
When the value of field 5 is 0, fields 6-9 and field A are nonexistent.
Field A includes repeated contents of fields 7-9 in turn. The number of repetitions
is equal to the value of field 5.
Field B includes repeated contents of fields 11-13 in turn. The number of
repetitions is equal to the value of field 10.
Field C indicates one of other fields in the MOBSCNREQ message.
FIG. 3 shows a format of an MOB_SCN_RSP message in the prior art. The format
of the MOBSCNRSP message is represented in the same way as that shown in FIG. 2.
Fields 1-14 are 14 fields that are represented by numbers and arranged in ascending order,

while fields 15-18 are four fields that are represented by numbers and arranged in
ascending order. The following describes each field shown in FIG. 3.
Field 1 is a management message type field of 8 bits.
Field 2 is a scan duration field of 8 bits.
Field 3 is a report mode field of 2 bits.
Field 4 is a reserved field of 6 bits.
Field 5 is a report period field of 8 bits.
Field 6 is a report metric field of 8 bits.
Field 7 is a start frame field of 8 bits.
Field 8 is an interleaving interval field of 8 bits.
Field 9 is a scan iteration field of 8 bits.
Field 10 is an N_Recommended_BS_Index field of 8 bits. This field indicates the
number of BS IDs that the BS intends to scan and that are included in the
MOBNBR-ADV message.
Fields 11-14 correspond to fields 6-9 shown in FIG. 2 in terms of content and
meaning. Field D between field 14 and field A is 24 bits long and is present only when the
scanning type of field 14 is scanning type 2 or scanning type 3.
Field A shown in FIG 3 includes repeated contents of fields 12-14 and field D in
turn. The number of repetitions is equal to the value of field 11. Field D is located between
field Hand field A.
Field 15 is an N_Recommended_BS_Full field of 8 bits. This field indicates the
number of BSs that the BS intends to scan and that are not included in the
MOB_NBR_ADV message.
Field 16 is a Recommended BS ID field of 48 bits. This field indicates the BS IDs
that the MS intends to scan and that are not included in the MOBNBRADV message.
Field 17 is a reserved field of 1 bit.

Field 18 is a scanning type field of 3 bits. This field indicates the scanning types of
the BS IDs in field 16.
Field D between field 18 and field B is 24 bits long and is present only when the
scanning type of field 18 is scanning type 2 or scanning type 3.
Field B shown in FIG. 3 includes repeated contents of fields 16-18 and field D in
turn. The number of repetitions is equal to the value of field 15. Field D is located between
field 18 and field B.
Field E indicates one of other fields in the MOBSCNRSP message.
Summary of the Invention
Embodiments of the present invention provide a method and apparatus for
responding to a scanning request to further improve the utilization rate of air interface
resources.
A method for responding to a scanning request in an embodiment of the present
invention comprises:
receiving a mobile scanning request MOB_SCN_REQ from an MS; and
responding to the MOBSCNREQ message, and sending a mobile scanning
response MOB_SCN_RSP to the MS, where:
the MOBSCNRSP message comprises a BS ID sequence indication field that maps
the BS IDs carried in the MOB_SCN_REQ message.
An apparatus for responding to a scanning request in an embodiment of the present
invention includes: a receiving unit, adapted to receive an MOBSCNREQ message; a
sequence indicating unit, adapted to map the BS IDs in the MOB_SCN_REQ message;
and a sending unit, adapted to send the MOB_SCN_RSP message according to the
mapping.
According to the method provided in an embodiment of the present invention, a BS
ID sequence indication field is set in the MOBSCNRSP message; and the BS ID

sequence indication field is used to map the BS IDs carried in the MOBSCNREQ
message. Thus, a BS ID may be mapped by using a field of less than 48 bits. Compared
with the Full BS ID in the prior art, the method provided in an embodiment of the present
invention can further improve the utilization rate of air interface resources. A sequence
indicating unit is also set in the apparatus provided in an embodiment of the present
invention, which also improves the utilization rate of air interface resources.
Brief Description of the Drawings
For better understanding of the technical solution provided in the embodiments of
the present invention or in the prior art, the following describes the accompanying
drawings that are used in the embodiments of the present invention or in the prior art.
Obviously, the following drawings are some exemplary embodiments of the present
invention only. Those skilled in the art may obtain other drawings based on the following
drawings without creative work.
FIG I shows a scanning process in the prior art;
FIG. 2 shows a format of an MOBSCNREQ message in the prior art;
FIG 3 shows a format of an MOB_SCN_RSP message in the prior art;
FIG 4 shows a scanning process provided in a first embodiment of the present
invention;
FIG. 5 shows a format of an MOBSCNRSP message in BS Index mode provided
in the first embodiment of the present invention;
FIG 6 shows a process of setting the MOBSCNRSP message in FIG. 5;
FIG. 7 shows a mapping relation between a BS Bitmap scanning type field and a
BS Bitmap field provided in the first embodiment of the present invention;
FIG. 8 shows multiple scanning processes initiated by an MS;
FIG. 9 shows a structure of an apparatus provided in a fourth embodiment of the
present invention; and

FIG 10 is a structure of a system provided in a fiftii embodiment of the invention.
Detailed Description of the Invention
During tiie implementation of the present invention, the inventor discovers at least
the following problems in the prior art:
Because one part of the BS IDs in a scanning process message may correspond to
the BS IDs in the MOBNBRADV message, this part of the BS IDs is represented in BS
Index mode in the prior art. When the BS IDs are represented in BS Index mode, each BS
needs 8 bits only; when the BS IDs are represented in Full BS ID mode, each BS needs 48
bit. Thus, if the first part of the BS IDs is represented in BS Index mode, the utilization
rate of air interface resources is improved. However, the second part of the BS IDs is still
represented in Full BS ID mode, which consumes high air interface resources. Because the
air interface resources are valuable, how to improve the utilization rate of air interface
resources is still an urgent problem to be solved for the wideband radio access system.
The technical solution of the present invention is hereinafter described in detail
with reference to the accompanying drawings. It is evident that the embodiments are only
exemplary embodiments of the present invention and the present invention is not limited
to such embodiments. Other embodiments that those skilled in the art obtain based on
embodiments of the present invention without creative work also fall in the scope of
protection of the present invention.
For better understanding of the objective, technical solution and merits of the
present invention, the present invention is hereinafter described in detail with reference to
accompanying drawings and exemplary embodiments.
First embodiment: After receiving an MOBSCNREQ message from the MS, the
BS sends an MOBSCNRSP message to the MS, responding to the scanning request of
the MS.

Among the BS IDs in the MOBSCNRSP message, the first part corresponds to
the BS IDs included in the MOBNBRADV message sent by the BS; the second part is
sent by the BS to respond to the MOBNBRREQ message; the third part is the BS IDs
that the BS intends to scan and that are not included in the MOBSCNREQ message.
The second part of the BS IDs is already carried in the MOBSCNREQ message and is
sequenced. For the second part of the BS IDs, the first embodiment optimizes the
MOBSCNRSP message as follows: A BS ID sequence indication field is set to map the
second part of the BS IDs. The BS ID sequence indication field may be set in BS Index
mode or in BS Bitmap mode. In BS Index mode, the BS ID sequence indication field is set
to a BS Index field; in BS Bitmap mode, the BS ID sequence indication field is set to a BS
Bitmap field.
The second part of the BS IDs sent by the BS to respond to the MOBSCNREQ
message may be set in two modes. First, the BS responds to all BS IDs carried in the
MOB_SCN_REQ message, where all the BS IDs include BS IDs mapped in Full BS ID
mode and in other modes; second, the BS responds to the BS IDs that are mapped in Full
BS ID mode and carried in the MOBSCNREQ message.
The following describes the method provided in the first embodiment based on the
first mode.
FIG. 4 shows a scanning process in which the BS responds to an MOBSCNREQ
message sent from the MS according to the method provided in the first embodiment of
the present invention.
Step 401: The MS sends to the BS an MOB_SCN_REQ message in which the
carried BS IDs are arranged in sequence. For example, if the MOB_SCN_REQ message
carries a total of three BS IDs, the BS IDs are arranged as follows: BS IDI, BS ID2, BS
ID3.
Step 402: After receiving the MOB_SCN_REQ message from the MS, the BS
sends an MOB_SCN_RSP message to the MS, where the MOB_SCN_RSP message maps

all the BS IDs carried in the MOBSCNREQ message in BS Bitmap mode or BS Index
mode.
The BS Index mode provided in the first embodiment is the same as that in the
prior art except for the following difference: The sequence in BS Index mode provided in
the first embodiment is the sequence of the BS IDs that are already carried in the
MOBSCNREQ message. In BS Index mode, the BS IDs carried in the
MOBSCNREQ message are mapped as follows by using the BS Index field: Each BS
ID has an index to indicate the sequence, and is identified by the index. For example, if the
index of a BS ID is 1 in the MOB_SCN_REQ message, I is used to identify the BS ID in
the MOB_SCN_RSP message. In BS Index mode, the value of the BS Index field is set to
the index to map the BS ID. In the first embodiment, only 8 bits are needed to map a BS
ID in BS Index mode. In contrast, 48 bits are needed in Full BS ID mode in the prior art.
In this embodiment, a BS Bitmap field is set in the MOBSCNRSP message to
represent the second part of the BS IDs in the MOB_SCN_RSP message in BS Bitmap
mode. The BS Bitmap field maps the BS ID. Preferably, the number of bits in the BS
Bitmap field is equal to the total number of BS IDs in the MOBSCNREQ message.
Each bit in the BS Bitmap is mapped to a BS ID among all the BS IDs. The sequence of
bits in the BS Bitmap field is mapped to the sequence of all the BS IDs. For example, the
first bit in the BS Bitmap field is mapped to the first BS ID among all the BS IDs. Each bit
in the BS Bitmap field uses 0 or 1 to indicate whether to request to scan a BS represented
by the BS ID that is mapped to the bit. For example, if a bit in the BS Bitmap field is set to
1 according to an agreement, the BS requests to scan a BS represented by the BS ID that is
mapped to the bit.
In practical applications, the number of bits in the BS Bitmap field may be smaller
than the total number of BS IDs. In this case, a bit in the BS Bitmap field is mapped to
multiple BS IDs among all the BS IDs. That is, when the MOBSCNRSP message has
one or multiple BS IDs, the bit mapped to multiple BS IDs is set to an agreed value. The

number of bits in the BS Bitmap field may also be greater than the total number of BS IDs.
In this case, multiple bits in the BS Bitmap field are mapped to a BS ID among all the BS
IDs. When the number of bits in the BS Bitmap field is smaller or greater than the total
number of BS IDs, the BS Bitmap field may be used with reference to the scenario where
the number of bits in the BS Bitmap field is equal to the total number of BS IDs in the
MOBSCNREQ message. A reserved bit may also be set in the BS Bitmap field, which
is not used to map all the BS IDs.
To map the BS IDs, the BS Bitmap field may map all the BS IDs or part of the BS
IDs that the MS requests to scan. For the specific mapping method in these two modes,
refer to related descriptions of embodiments of the present invention. For the mapping
between the BS index field and the BS IDs, refer to related descriptions of the mapping
between the BS Bitmap field and the BS IDs.
Compared with the Full BS ID mode in the prior art in which 48 bits are needed,
only one bit is needed to map a BS ID in BS Bitmap mode.
In the preceding first mode, the index in BS Index mode is the index of the BS ID
among all the BS IDs.
When the BS Index mode is used in the second mode, the index of a BS ID is the
index of the Full BS ID among all the BS IDs mapped in Full BS ID mode in an
MOB_SCN_REQ message. Preferably, when the BS Bitmap mode is used, the number of
bits in the BS Bitmap field is equal to the number of BS IDs mapped in Full BS ID mode
in the MOBSCNREQ message. In the preceding second mode, the BS Index mode and
the BS Bitmap mode may be used with reference to the first mode, and will not be further
described.
Preferably, a carrying indication field is set in a current MOBSCNRSP message
to indicate whether the MOB_SCN_RSP message comprises BS IDs that are already
carried in an MOBSCNREQ message. This indication field may use one of six bits
reserved in the current MOB_SCN_RSP message, one of other fields in the current

MOBSCNRSP message or a new field with a variable length. The carrying indication
field is optional. Without the carrying indication field, the MOBSCNRSP message may
also use the BS Bitmap mode or BS Index mode directly.
FIG 5 shows a format of an MOBSCNRSP message in BS Index mode.
Compared with FIG. 3, FIG. 5 has the following differences: An MSR Ind field is
inserted between field 3 and field 4; fields 19-22, field D and field F are inserted between
field B and field E. The following describes each field shown in FIG. 5.
Fields 1-3, fields 4-14, field A, field D between field 14 and field A, and field E
shown in FIG. 5 are the same as those fields with the same labels and relative positions
shown in FIG 3 in terms of contents and meanings. Compared with the fields with the
same labels and relative positions shown in FIG. 3, fields 15-18, field B and field D
between field B and field 18 shown in FIG. 5 have only the following difference: The BS
IDs in those fields shown in FIG. 5 are BS IDs that a BS intends to scan, that is, the third
part of BS IDs.
In FIG. 5, field 19 is used to map the number of BS IDs that are already carried in
the MOB_SCN_REQ message and should be carried in the MOBSCNRSP message,
that is, the number of the second part of BS IDs. Field 19 is 8 bits long; field 20 is an
index of the BS ID in the MOBSCNREQ message and is 8 bits long; field 21 is a
reserved field of 1 bit; field 22 indicates a scanning type of the BS ID mapped in field 20;
field D between field 22 and field F is 24 bits long and is present only when the scanning
type is scanning type 2 or scanning type 3; field F is used to repeat the contents in fields
19-22 and field D, and the number of repetitions is equal to the value of field 19.
The MSR Ind field is the carrying indication field, which is used to indicate
whether the MOBSCNRSP message comprises BS IDs that are already carried in the
MOBSCNREQ message. For example, when the value of the MSR Ind field is agreed to
be 1, the MOBSCNRSP message comprises BS IDs that are already carried in the
MOBSCNREQ message. If the value of the MSR Ind field is agreed to be 1, fields

19-22, field F, and field D between field F and field 22 are present; otherwise these fields
are nonexistent.
FIG 6 shows a process of setting the format of an MOBSCNRSP message.
Step 601: Set fields 1-3, the MSR Ind field, and fields 4-6.
Step 602: Judge whether the value of field 2 is a non-zero value; if so, proceed to
step 603; otherwise, go to step 610.
Step 603: Set fields 7-10.
Step 604: Judge whether the value of field 10 is a non-zero value; if so, proceed to
step 605; otherwise, go to step 606.
Step 605: Set fields 11-14, field A, and field D between field A and field 14.
Step 606: Set fields 15-18, field B, and field D between field B and field 18.
Step 607: Judge whether the value of the MSR Ind field is 1; if so, proceed to step
608; otherwise, go to step 609.
Step 608: Set fields 19-22, field F, and field D between field F and field 22.
Step 609: Set field E.
Step 610: The setting process ends.
For the method for setting each field shown in FIG 6, refer to related descriptions
of embodiments of the present invention, and the method will not be further described.
In FIG. 5 and FIG. 6, the carrying indication field MSR Ind may use one of six bits
reserved in the MOB_SCN_RSP message. In practical applications, the MSR Ind field
may use one or multiple bits among other bits or a new field with a variable length in the
MOBSCNRSP message.
When the second part of the BS IDs in the MOB_SCN_RSP message is
represented in BS Bitmap mode, the diflference between the format of the
MOBSCNRSP message and that shown in FIG. 5 is as follows: Fields 19-22 shown in
FIG 5 are replaced with the BS Bitmap field; field D between field F and field 22 shown

in FIG. 5 is replaced witii the BS Bitmap scanning type field; and field F is present only
when the BS Bitmap scanning type field comprises scanning type 2 or scanning type 3.
For the method for setting the BS Bitmap field, refer to related descriptions of
embodiments of the present invention.
Bits in the BS Bitmap scanning type field indicate a scanning type. Starting from
the initial bit of the scanning field, every 3 bits indicate a scanning type. The sequence of
scanning types corresponds to the values and sequences of bits in the BS Bitmap field.
This is described in detail with reference to FIG. 7.
The BS Bitmap field in FIG. 7 is 5 bits long, and indicates that the number of BS
IDs carried in the MOBSCNREQ message is 5. The first bit in FIG. 7 corresponds to the
first BS ID in the MOBSCNREQ message, and the rest of bits correspond to the rest of
BS IDs in the MOBSCNREQ message in turn. In FIG 7, when the value of a bit is 1,
the BS requests to scan a BS represented by a BS ID that is mapped to the bit, and the bit
corresponds to a 3-bit scanning type field. Scanning types that correspond to each bit
whose value is 1 in the BS Bitmap field are arranged in the sequence of the bits. As shown
in FIG 7, the values of the second bit and the fourth bit in the BS Bitmap field are I. Thus,
the scanning type that corresponds to the second bit is represented by the first 3 bits in the
BS Bitmap scanning type field, while the scanning type that corresponds to the fourth bit
is represented by the second 3 bits in the BS Bitmap scanning type field. In the BS Bitmap
scanning type field shown in FIG. 7, 0, 1 and 2 indicate that the bit is bit 0, bit 1 and bit 2
in the 3 bits.
If the second part of BS IDs in the MOBSCNRSP message uses the BS Bitmap
mode, the process of setting the MOBSCNRSP message is similar to that shown in FIG
6 except that step 608 is changed as follows:
Set the BS Bitmap field, BS Bitmap scanning type field and field F.
In this embodiment, the MOBSCNRSP message is optimized. For BS IDs that
are already carried in the MOBSCNREQ message, the BS Index mode or BS Bitmap

mode is used in the MOBSCNRSP message to map the BS IDs. In BS Index mode, only
8 bits are needed to map each BS ID; in BS Bitmap mode, at least one bit is needed to map
each BS ID. In current Full BS ID mode, 48 bits are needed to map each BS ID. Thus, the
method provided in this embodiment of the present invention may greatly improve the
utilization rate of air interface resources.
Second embodiment: A message ID field is set in a scanning process message to
identify each scanning process message, so that the MOB_SCN_REQ matches the
MOBSCNRSP message. When multiple scanning processes are available at a time, the
message ID field may specify which MOBSCNREQ message matches an
MOBSCNRSP message. Thus, the message ID field may be used to match the
MOB_SCN_REQ message with the MOBSCNRSP message. The message ID field may
be named "Configuration change count for MOBSCNREQ", "Transaction ID" or
"Sequence Number". The length of the message ID field may be 1-32 bits or more. The
message ID field may be a new field with a variable length, an existing field, or one or
multiple bits of an existing field in the scanning process message.
The following gives an example to describe how to use the message ID field.
Supposing the message ID field is 2 bits long, the message ID field may match four pairs
of scanning process messages because 2 bits may represent four numbers, that is, 0-3. The
specific matching method is as follows: A message ID field is set in an MOBSCNREQ
message and an MOBSCNRSP message; when the value of the message ID field in the
MOBSCNRSP message is the same as that in the MOBSCNREQ message, the
MOBSCNRSP message matches the MOBSCNREQ message. For example, when an
MS sends an MOBSCNREQ message, the MS sets the ID field in the MOBSCNREQ
message to 1; after a BS receives the MOB_SCN_REQ message, the BS sends an
MOB_SCN_RSP message, and also sets the message ID field in the MOB_SCN_RSP
message to 1, which specifies that the MOBSCNRSP message matches the
MOB_SCN_REQ message with the ID 1.

A message ID field is added to a scanning process message to specify which
MOBSCNREQ message matches an MOBSCNRSP message. In this case, errors may
be avoided when the method provided in the first embodiment of the present invention is
used to scan. The reasons are as follows: If the message ID field is not included in the
scanning process message, the MOBSCNRSP message matches a latest
MOBSCNREQ message that the MS sends according to the prior art; however, after the
MS sends an MOBSCNREQ message actively, a BS does not receive the message due
to transmission errors; in this case, the BS sends an MOBSCNRSP message to the MS
actively, but the MS cannot judge whether the MOBSCNRSP matches the
MOBSCNREQ message or is sent by the BS actively. In this embodiment, the
preceding errors are avoided because a message ID field is used to match the scanning
process messages.
After a message ID field is added to the scanning process messages, the preceding
errors are avoided and multiple scanning processes may be initiated by the MS or BS. The
following describes this embodiment in detail, supposing the MS initiates multiple
scanning processes.
FIG. 8 shows multiple scanning processes initiated by an MS after a message ID
field is added.
As shown in FIG. 8, the MS sends two MOBSCNREQ messages to a BS. The
message ID field is set to 1 in one MOBSCNREQ message and to 2 in the other
MOB_SCN_REQ message. The BS sends two MOBSCNRSP messages. The message
ID field is set to 1 in one MOBSCNREQ message and to 2 in the other
MOB_SCN_REQ message. After receiving the MOBSCNRSP messages, the MS may
know that the MOB_SCN_RSP message with the message ID field 2 matches the
MOB_SCN_REQ message with the message ID field 2, and that the MOB_SCN_RSP
message with the message ID field 1 matches the MOBSCNREQ message with the
message ID field 1. Thus, when an MS sends multiple MOBSCNREQ messages, the

MS may judge which MOBSCNREQ message matches an MOBSCNRSP message
according to the message ID field. The initiating of multiple scanning processes by the MS
may be: initiating multiple scanning processes by the MS at the same time, or initiating
multiple scanning processes in sequence by the MS.
Third embodiment: A mode indication field is further set in a scanning process
message to indicate whether the scanning process message uses the BS Bitmap mode or
BS Index mode. The mode indication filed is used to indicate which mode a current
scanning process message uses. Subsequent scanning process messages will use the mode
indicated by the mode indication field. It should be noted that a message may use either
the BS Index mode or the BS Bitmap mode only. The message can select a proper mode
according to the actual situation. The mode indication field may be a format indication bit
(FMT bit), a field including multiple bits, or a bit in the mode indicafion field.
Fourth embodiment: This embodiment provides an apparatus for responding to a
scanning request.
The apparatus comprises a receiving unit, a sending unit, and a sequence indicating
unit, where: the receiving unit is adapted to receive an MOB_SCN_REQ message; the
sending unit is adapted to send an MOBSCNRSP message; and the sequence indicating
unit is adapted to map an information unit in the receiving unit.
Preferably, the apparatus further comprises an information unit, which is adapted to
store BS IDs in the MOB_SCN_REQ message received by the receiving unit. The
information unit may further include a mode indication unit, which is adapted to indicate a
structure of the sequence indicating unit.
The information unit may further include a carrying indication unit, which is
adapted to indicate whether the receiving unit includes the information unit.
The sequence Indicating unit in this embodiment may be a BS Index unit or a BS
Bitmap unit.

The BS Bitmap unit comprises a subunit, whicii is adapted to map tiie information
unit. The location of the subunit corresponds to the sequence of the BS ID in the
MOBSCNREQ message. The subunit is set to indicate whether the scanning message
comprises the BS ID of the sequence. The number of subunits may be equal to the number
of information units or number of Full BS IDs in the information unit.
The apparatus provided in this embodiment further comprises a
reception/transmission identifying unit, which is adapted to match the MOBSCNRSP
message sent by the sending unit with the MOBSCNREQ message received by the
receiving unit.
The following further describes the apparatus provided in this embodiment with
reference to FIG. 9.
As shown in FIG. 9, 900 represents the apparatus; 910 represents the receiving unit;
920 represents the carrying indication unit; 930 represents the sequence indicating unit;
940 represents the sending unit; 950 represents the mode indication unit; 911 represents
the reception/transmission identifying unit in the receiving unit; 912 represents the
information unit; 931 represents the BS Bitmap unit; and 932 represents the BS Index unit.
The information unit comprises a carrying indication unit and a mode indication
unit, and the sequence indicating unit comprises a BS Bitmap unit and a BS Index unit.
The receiving unit 910 receives an MOBSCNREQ message, and stores the BS
ID in the MOBSCNREQ message in the information unit 912; the
reception/transmission identifying unit 911 in the receiving unit stores the message ID
field in the MOB_SCN_REQ message.
The carrying indication unit 920 receives a message from the receiving unit 910
and judges whether the information unit 912 exists; if so, the carrying indication unit 920
sends carrying indication information to the sequence indicating unit 930; after receiving
the carrying indication information, the sequence indicating unit 930 receives the message
from the receiving unit 910; the sequence indicating unit 930 is adapted to: map BS IDs in

the information unit 912, obtain BS ID sequence indication information after tiie mapping,
and send the BS ID sequence indication information to the sending unit 940. The sending
unit 940 receives the BS ID sequence indication information, and sets the message ID field
in the reception/transmission identifying unit 941 of the sending unit to a value that the is
same as or corresponds to the value of the message ID field in the reception/transmission
identifying unit 911 of the receiving unit. Then, the sending unit 940 sends an
MOB_SCN_RSP message externally, where the MOB_SCN_RSP message carries the BS
ID sequence indication information and the message ID field.
The sequence indicating unit 930 may use the structure of the BS Bitmap unit 931
or BS Index unit 932. The mode indication unit 950 sends mode indication information to
the sequence indicating unit 930 to indicate whether the sequence indicating unit 930 uses
the structure of the BS Bitmap unit 931 or the BS Index unit 932. It should be noted that
only the BS Bitmap unit 931 or the BS Index unit 932 is available.
In practical applications, there may be one or multiple information units 912.
When there are multiple information units 912, each of the information units is arranged in
a sequence same as that of BS IDs in the MOBSCNREQ message.
The BS Bitmap unit 931 comprises a subunit, which is not illustrated in FIG 9.
The location of the subunit corresponds to the location of the information unit 912. The
subunit is set to indicate whether the MOB_SCN_RSP message comprises contents of the
information unit.
The BS Index unit 932 is set according to the location of an information unit
among all the information units 912 that stores BS IDs that the apparatus 900 wants to
carry in the MOBSCNRSP message. The number of BS Index units 932 is equal to the
number of BS IDs that the apparatus 900 wants to carry in the MOB_SCN_REQ message
and that are also included in the MOBSCNREQ message.
In FIG. 9, the units 920, 950, 911 and 941 are optional units.

Fifth embodiment: This embodiment provides a system for responding to a
scanning request.
The system provided in this embodiment includes an MS, a BS, and a sequence
indicating unit, where: the MS is adapted to send an MOBSCNREQ message; the BS is
adapted to receive the MOBSCNREQ message and send an MOBSCNRSP message;
and the sequence indicating unit is located in the BS and adapted to map the information
unit in the MOBSCNREQ message.
Preferably, the system further comprises a mode indication unit, which is located in
the BS and adapted to indicate the structure of the sequence indicating unit.
Preferably, the system further comprises a carrying indication unit, which is
located in the BS and adapted to indicate whether the BS comprises the information unit.
Preferably, the system further comprises a reception/transmission identifying unit,
which is located in the MS and BS and adapted to match the MOB_SCN_RSP message
with the MOB_SCN_REQ message.
The following further describes the system provided in this embodiment with
reference to FIG. 10.
In FIG. 10, 1000 represents the BS; 1001 represents the MS; 1060 represents the
sending unit of the MS; 1061 represents the reception/transmission identifying unit in the
sending unit 1060 of the MS; 1070 represents the receiving unit of the MS; 1071
represents the reception/transmission identifying unit in the receiving unit 1070 of the MS;
1010 represents the receiving unit of the BS; 1011 represents the reception/transmission
identifying unit in the receiving unit 1010 of the BS; 1012 represents the information unit;
1020 represents the carrying indication unit; 1030 represents the sequence indicating unit;
1031 represents the BS Bitmap unit; and 1032 represents the BS Index unit; 1040
represents the sending unit of the BS; 1041 represents the reception/transmission
identifying unit in the sending unit 1040 of the BS; and 1050 represents the mode
indication unit.

The internal structure of the BS 1000 shown in FIG. 10 corresponds to that of the
apparatus 900 shown in FIG. 9 according to the last two digits of the numbers in the
drawings and so is the mapping relation between the units. That is, the last two digits of
the BS 1000 are the same as those of the apparatus 900 in the drawings, and so are the
internal structures of the units represented by the numbers in the drawings and mapping
relation between the units.
In FIG. 10, the sending unit 1060 of the MS 1001 sends an MOBSCNREQ
message to the receiving unit 1010 of the BS 1000, where the MOBSCNREQ message
carries a message ID field generated by the reception/transmission identifying unit 1061;
the receiving unit 1070 of the MS 1001 receives an MOB_SCN_RSP message from the
sending unit 1040 of the BS 1000, and stores a message ID field carried in the
MOB_SCN_RSP message in the reception/transmission identifying unit 1071; the
reception/transmission identifying unit 1071 receives the message ID field from the
reception/transmission identifying unit 1061, and judges whether the message ID field
carried in the MOBSCNRSP message is the same as or corresponds to the message ID
field sent from the reception/transmission identifying unit 1061; if so, the
MOBSCNRSP message matches the MOB_SCN_REQ message; otherwise, the
MOBSCNRSP message does not match the MOBSCNREQ message.
In FIG. 10, the units 1020, 1050, lOIl, I04I, 1061 and 1071 are optional units.
For the sequence indicating unit, BS Bitmap unit, BS Index unit, mode indication
unit, carrying indication unit, reception/transmission identifying unit and other units in the
apparatus provided in the fourth embodiment and system provided in the fifth embodiment,
the internal structures are set according to the method provided in an embodiment of the
present invention, and will not be further described.
According to the preceding solution, an MOBSCNRSP message is optimized.
For BS IDs that are already carried in an MOB_SCN_REQ message, the MOB_SCN_RSP
message provided in embodiments of the present invention is represented in BS Index

mode or BS Bitmap mode. The sequences used in BS Index mode and BS Bitmap mode
are sequences of the BS IDs in the MOBSCNREQ message. When the
MOBSCNRSP message is represented in BS Index mode or BS Bitmap mode, each of
BS IDs that are already carried in the MOBSCNREQ message is represented by 8 bits
or 1 bit only. In contrast, 48 bits are needed in Full BS ID mode in the prior art. Thus, the
method provided in embodiments of the present invention can greatly improve the
utilization of air interface resources.
In embodiments of the present invention, a message ID field is further set to match
the MOB_SCN_RSP message with the MOB_SCN_REQ message, so that the MS or BS
can initiate multiple scanning processes without errors during the matching between the
MOBSCNRSP message and the MOB_SCN_REQ message.
In embodiments of the present invention, a mode indication mode is further set to
indicate whether a current scanning process message uses the BS Bitmap mode or BS
Index mode, which can achieve the compatibility between the BS Bitmap mode and the
BS Index mode. Thus, different modes may be selected according to different scenarios,
and the utilization of air interface resources may be maximized.
Through the preceding description of embodiments of the present invention, it is
understandable to those skilled in the art that embodiments of the present invention may
be implemented by hardware or by software in combination with a necessary hardware
platform. Thus, the technical solution of the present invention may be made into software.
The software may be stored in a non-volatile storage medium (for example, a CD-ROM, a
USB disk, or a mobile hard disk), and include several instructions that instruct a computer
device (a personal computer, a server, or a network device) to execute the method
provided in each embodiment of the present invention.
Although the present invention has been described through several exemplary
embodiments, the invention is not limited to such embodiments. It is apparent that those
skilled in the art can make various modifications and variations to the invention without

departing from the spirit and scope of the invention. The invention is intended to cover the
modifications and variations provided that they fall in the scope of protection defined by
the following claims or their equivalents.

WE CLAIM:
1. A method for responding to a scanning request, comprising:
receiving a mobile scan request MOBSCNREQ message sent by a mobile station
( MS ) ; and
responding to the MOBSCNREQ message by sending a mobile scanning response
message MOBSCNRSP to the MS, wherein
the MOBSCNRSP message comprises a base station ( BS ) ID sequence
indication field which maps the BS IDs carried in the MOB_SCN_REQ message.
2. The method for responding to a scanning request according to claim 1, wherein
the MOB_SCN_RSP message further comprises a carrying indication field, adapted
to indicate whether the BS IDs in the MOBSCNREQ message are carried in the
MOB_SCN_RSP message.
3. The method for responding to a scanning request according to claim I, wherein
the MOBSCNRSP message further comprises a mode indication field, adapted to
indicate how the BS ID sequence indication filed is set.
4. The method for responding to a scanning request according to claim 1, wherein
the BS ID sequence indication field is set as a BS Index field and the BS Index field
maps the BS IDs carried in the MOBSCNREQ message.
5. The method for responding to a scanning request according to claim 1, wherein
the BS ID sequence indication field is set as a BS Bitmap field and the BS Bitmap
field maps the BS IDs carried in the MOBSCNREQ message.

6. The method for responding to a scanning request according to claim 5, wherein the
process the BS Bitmap field maps the BS IDs carried in the MOBSCNREQ message
comprises:
the position of each bit in the BS Bitmap field maps a BS ID in the corresponding
position of the BS IDs; and
the value of each bit in the BS Bitmap field indicates whether the corresponding BS
ID is carried in the MOBSCNRSP message.
7. The method for responding to a scanning request according to claim 6, wherein the
number of bits in the BS Bitmap field is set as the number of BS IDs.
8. The method for responding to a scanning request according to claim 6, wherein the
number of bits in the BS Bitmap field is set as the number of Full BS ID in the BS IDs.
9. The method for responding to a scanning request according to any one of claims 1
-8, wherein a message ID field is set in the MOBSCNREQ message and the
MOB_SCN_RSP message.
10. An apparatus for responding to a scanning request, comprising:
a receiving unit, adapted to receive an MOBSCNREQ message;
a sequence indicating unit, adapted to map the BS IDs in the MOBSCNREQ
message; and
a sending unit, adapted to send an MOBSCNRSP message according to the
mapping.
11. The apparatus for responding to a scanning request according to claim 10, further
comprising:
an information unit, adapted to store BS IDs in the MOBSCNREQ message
received by the receiving unit.
12. The apparatus for responding to a scanning request according to claim 11,
wherein the information unit further comprises:

a mode indication unit, adapted to send mode indication information to the sequence
indicating unit; and
the sequence indicating unit, adapted to judge the structure of the sequence indicating
unit according to the mode indication message.
13. The apparatus for responding to a scanning request according to claim 11,
wherein the information unit further comprises:
a carrying indication unit, adapted to acquire the number of BS IDs and send carrying
indication information to the sequence indicating unit according to the number.
14. The apparatus for responding to a scanning request according to claim 10,
wherein the sequence indicating unit further comprises:
a BS Index unit, adapted to map BS IDs by BS Index.
15. The apparatus for responding to a scanning request according to claim 10,
wherein the sequence indicating unit further comprises:
a BS Bitmap unit, adapted to map BS IDs by BS Bitmap.
Dated this 29* day of December 2009

A method for responding to a scanning request comprises these steps: A base station
(BS) receives a mobile scanning request (MOB_SCN_REQ) from a mobile station (MS);
the BS responds to the MOB_SCN_REQ message and sends a mobile scanning response
(MOB_SCN_RSP) to the MS, where the MOB_SCN_RSP message comprises a base
station identity (BS ID) sequence indication field that maps BS IDs carried in the
MOB_SCN_REQ message. An apparatus for responding to a scanning request comprises a
sequence indicating unit. The method and apparatus may improve the utilization of air
interface resources.

Documents:

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Patent Number

270240

Indian Patent Application Number

4532/KOLNP/2009

PG Journal Number

49/2015

Publication Date

04-Dec-2015

Grant Date

03-Dec-2015

Date of Filing

29-Dec-2009

Name of Patentee

HUAWEI TECHNOLOGIES CO., LTD.

Applicant Address

HUAWEI ADMINISTRATION BUILDING, BANTIAN, LONGGANG DISTRICT, SHENZHEN, GUANGDONG 518129, P.R. CHINA

Inventors:

#	Inventor's Name	Inventor's Address
1	MO, JUNXIAN	HUAWEI ADMINISTRATION BUILDING, BANTIAN, LONGGANG DISTRICT, SHENZHEN, 518129, GUANGDONG, P.R. CHINA
2	COMSTOCK, DAVID	HUAWEI ADMINISTRATION BUILDING, BANTIAN, LONGGANG DISTRICT, SHENZHEN, 518129, GUANGDONG, P.R. CHINA

PCT International Classification Number

H04Q 7/38

PCT International Application Number

PCT/CN2008/072297

PCT International Filing date

2008-09-08

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	200710181372.9	2007-10-20	China