Title of Invention	A MULTI GIGAHERTZ HIGH CAPACITY DIGITAL RADIO FREQUENCY (RF) LINK TRANSCEIVER TERMINAL DEVICE AND METHOD FOR SAME
Abstract	A multi gigahertz digital radio frequency (RF) link terminal device is disclosed. The device comprises an indoor unit and an outdoors connected by at least one high bandwidth communications means adapted to carry in a transmit direction a digital signal to be transported by said radiolink and in a receive direction an intermediate frequency digital RF receive signal to be transported by clink. The outdoor unit includes an RF digital modulator integrated with a multi gigahertz digital RF amplifier assembly and at least two multi gigahertz digital RF receiver circuit assemblies, each having a multi gigahertz digital RF receive signal input and outputs for providing a respective one of a intermediate frequency digital RF receive signal. The indoor unit includes at least two RF digital demodulators having each an input for receiving at least one of the intermediate frequency digital RF receive signals, and said at least two RF digital demodulators being adapted to exchange signal demodulation processing data to allow mutual optimization of demodulation of said- intermediate frequency digital RF receive signal.

Title of Invention

A MULTI GIGAHERTZ HIGH CAPACITY DIGITAL RADIO FREQUENCY (RF) LINK TRANSCEIVER TERMINAL DEVICE AND METHOD FOR SAME

Abstract

A multi gigahertz digital radio frequency (RF) link terminal device is disclosed. The device comprises an indoor unit and an outdoors connected by at least one high bandwidth communications means adapted to carry in a transmit direction a digital signal to be transported by said radiolink and in a receive direction an intermediate frequency digital RF receive signal to be transported by clink. The outdoor unit includes an RF digital modulator integrated with a multi gigahertz digital RF amplifier assembly and at least two multi gigahertz digital RF receiver circuit assemblies, each having a multi gigahertz digital RF receive signal input and outputs for providing a respective one of a intermediate frequency digital RF receive signal. The indoor unit includes at least two RF digital demodulators having each an input for receiving at least one of the intermediate frequency digital RF receive signals, and said at least two RF digital demodulators being adapted to exchange signal demodulation processing data to allow mutual optimization of demodulation of said- intermediate frequency digital RF receive signal.

Full Text	Field of invention The present invention relates to a multi gigahertz high capacity digital radio frequency (RF) link transceiver terminal device, and method for same. The field of application for the present invention may generally be labelled "high capacity microwave radio", and more specifically such kind of microwave radio link solutions that offer very high quality, very high reliability, point-to-point or point-to-multipoint communication with capacities beyond 8Mb/s wireless communication at microwave frequencies. In the context of the present invention, microwave frequencies are understood to include the range 3GHz to 100GHz. The field of interest is in particular described in terms of the variability and complexity of the possible installations, ranging from single channel solutions without interaction with other radios to more complex installations requiring access to more than one receive signal for successful operation. Application like MIMO systems (Multiple Input, Multiple Output) and future interference mitigation solutions are considered to be of relevance to the present invention. Known solutions and problems with these High capacity radio systems serve a variety of communication needs, and the great range of potential applications makes it natural to explain this invention in the light of technology and logistics, reflecting the kind of problem it aims to solve. The traditional applications are described by Freeman, Roger L., "Radio System Design for Telecommunications", Second Edition (New York: John Wiley & Sons, 1997), giving an introduction to the application background for the invention. Norwegian patent application no 20034776, filed 24. Oct. 2003 When making radio systems for trunk and mobile backhaul point-to point communication, it turns out that the conventional arrangement/device of the functional units does not allow exploitation of technology advances for efficient radio transmitters. Point-to point high capacity radios operate at high frequencies, traditionally requiring line-of sight between the two antennas. The antennas often have to be placed in towers or other inconvenient locations with respect to access and maintenance. It is often highly desirable to have the transmit power amplifier as close to the antenna as possible in order to avoid power loss. For the same reason it is desirable to have the receive low noise amplifier close to the antenna. The split of radio installations into an outdoor unit and an indoor unit is natural. The outdoor unit should be robust and as simple as possible, and if one can afford the losses by separating the antenna from the transmit power amplifier and the receiver low noise amplifier, we may find that only the antenna belongs to the outdoor unit For solutions in a product portfolio where this is not always the case, it has become common to designate all functional units that may need to be located outdoors in some installations as outdoor functions. As we only need to have channel frequency specific hardware in the outdoor functions, it has become common practice to class all channel frequency dependant hardware as outdoor functions, assuming communication with functions in the indoor unit at one or more fixed frequencies. The importance of this interface solution is shown by the fact that the outdoor unit actually includes the functional units on the antenna side of the abovementioned fixed frequency interface, regardless of whether these functional units are placed indoors or outdoors, meaning that what is typically referred to as the outdoor unit can in fact be distributed as, for example, an outdoor antenna and an indoor transceiver. Likewise would all functional units separated from the antenna by the abovementioned fixed frequency interface belong to the indoor unit. This fixed, typically intermediate frequency interface between the outdoor unit and the indoor unit enables a standardization that makes the indoor unit hardware frequency independent. The implementation also is very effective. In the outdoor unit one only needs to shift the frequencies between the specific radio channels and the selected intermediate frequencies. The modulator and the demodulator of the indoor unit are not more costly due to the extra frequency conversion. Adding management messages and power supply to the same cable effectively completes a general interface allowing very flexible product arrangements devices. An illustration of this basic arrangement/device is provided in figure 1, giving the opportunity to define some terminology useful for the following descriptions. At the far right, an antenna is indicated in location A, closely connected to a frequency separation solution, marked D. The frequency separation solution can be a diplexer or more complex branching arrangements/devices. The signal prepared for wireless transmission, C2, and the received signal, C3, from the antenna are identified here. To the left of the frequency separation solution (D), we find two functional units, numbered 2 and 3, and collectively labeled M2 as an abbreviation for "module 2", often named a transceiver. Functional unit 2 performs frequency translation and amplification of the transmit signal, while functional unit 3 performs low-noise amplification and frequency translation of the receive signal. The outdoor unit hence contains the units labeled A, D and M2. The functional units 2 and 3 are kept together in a common module because they represent units that are most likely to need service in the outdoor unit, and efforts have been made to ease replacement service by non-specialists. Depending on product, M2 and D may be integrated as well. The module M1 is 'part of the indoor unit of the radio system, containing the modulator unit 1 and the demodulator unit 4 for the specific radio. The interface towards the outdoor unit is as described above. We identify the transmit signal, C5, and the received signal, C6, both having chosen,fixed frequencies. A cable based connection, covering distances from 1 to 300 meters between M1 and M2 provides an effective communication solution. Input digital data for wireless transmission, labeled C1, are received in the modulator unit 1. Output digital data, demodulated from the received signal, are provided from the demodulator 4, at the interface labeled C4. There is significant cost associated with the generation of the transmit signal with required quality. Recent developments, such as what is disclosed in Norwegian patent application no 20034776, filed by the present applicant on 24. Oct. 2003, have created further potential for improvement in the transmit chain, having an important impact on system cost, output power, linearity and efficiency of the power amplifier. To take full advantage of these advancements, the modulator unit 1 and the circuits at channel frequency, including the power amplifier,must work in close cooperation, which in turn requires physical proximity. Known arrangements/ devices (radio architectures) are not capable of taking full advantage of such solutions due to the physical distances that traditionally separate the indoor unit from the outdoor unit, which may be as large as up to 300 meters. Until now, the skilled person in the art has chosen the obvious solution to this problem, namely to move both modulator and demodulator to the outdoor unit, thereby eliminating the interfaces at C5 and C6. Thus, by communication of the input data and the output data at C1 and C4, respectively, directly to the outdoor unit, as known from in present day technology, a straightforward solution is available. This straightforward solution, however, does not address the thereby incurred problems of maintainability and other important operational aspects, which all tend to add cost and other design considerations in order to meet the stringent performance requirements that typically are presented by radio link operators. Furthermore, in installations with more than one radio channel, quality and availability requirements, in conjunction with the desire to utilize the spectrum as efficiently as possible, often require the demodulators to cooperate. One example of this is the use of two, or even more, polarizations in a radio link. Briefly, the antennas are arranged to excite and receive signals at, for example, orthogonal polarizations, thereby multiplying the spectrum utilization. However, in the case of orthogonal polarization, perfect orthogonality is a rare event, and there is need for interference mitigation in order to arrive at the expected performance. If a demodulator receives the signal from both polarizations, it is possible to solve this task. The traditional solution to this is illustrated in figure 2, being characterized by the need to exchange the received signal between the two demodulators. This transfer of received signals is labeled C7. Other arrangements/devices exist, requiring similar transfers of signals, giving cross connections similar to what is shown in figure 3. One or more antennas may be used. The essential feature is that some of the demodulators need access to the receive signals from one or more other receivers. If the demodulators are placed in respective outdoor units for such system arrangements/ devices, then cross-links between the demodulators outdoors must to be provided. It is clear that such an arrangement/device will incur significant costs. To date, the industry has tried to improve the transmit chain cost and performance for complex radio installations without taking advantage of the potential associated with close connection between the modulator and channel frequency dependant hardware, including the power amplifier. The inventors of the present invention do not know of any previously known solution to this challenge of the type disclosed herein. Brief description and objects of the invention According to the present invention, it is proposed to separate the modulator and demodulator units, whereby it becomes possible to take advantage of benefits in the transmit chain while maintaining the advantages of having an indoor demodulator. The idea of such a separation results in some complications to be overcome. The choice to do so and the measures taken to overcome the associated obstacles are material to the invention. The major benefits become apparent when a complete product portfolio is to be created that supports a variety system solutions that range from from single channel radios with just one transmitter and one receiver to complex systems that for performing one or more demodulation tasks require access to more than one of the received radio signals. The typical solution of optimised hardware for the different configurations is not a viable alternative, as customers often want flexibility and options for further expansion, and because the average number of installations per configuration typically is limited. In order to arrive at a solution that enables a common hardware platform to support all configurations of interest in a cost effective manner, it is an important choice not to integrate the frequency separating unit with the module M2, as seen in figure 4 and figure 5, where the transmit and receive signals are simply labelled C2 and C3. This enables assembly of simple, diplexer based, installations using the same modules as those employed in more complex solutions that are based on branching. A further object of the invention is to take advantage of a common mechanical solution. Such a solution must cope with all product configurations, including variants with high output power that may have demanding thermal requirements. Exploitation of the integrated transmit chain and the solution disclosed in Norwegian patent application no 20034776, filed 24. Oct. 2003, to obtain maximum power efficiency by means of e.g. dynamic biasing schemes in installations requiring high output power, eases the thermal requirements significantly. In the context of the present invention, this new technology further enhances the enablement of one common mechanical solution for a complete product range that does not add what previously has been considered unacceptable cost. In a first aspect, the present invention provides a multi gigahertz digital radio frequency (RF) link terminal device comprising an indoor unit and an outdoor unit interconnected by at least one high bandwidth communications means for carrying in a transmit direction a digital signal to be transported by said radiolink and in a receive direction an intermediate frequency digital RF receive signal to be transported by said radiolink. The outdoor unit includes an RF digital modulator integrated with a multi gigahertz digital RF amplifier assembly, said RF digital modulator having an input adapted for receiving said digital signal to be transmitted by said radiolink, and at least two multi gigahertz digital RF receiver circuit assemblies adapted for receiving a multi gigahertz digital RF receive signal and having an output each for providing a respective one of said intermediate frequency digital RF receive signal. The indoor unit including at least two RF digital demodulators having each an input adapted for receiving at least one of said respective one of said intermediate frequency digital RF receive signal. The at least two RF digital demodulators are provided with a means for exchanging signal demodulation processing data to allow mutual optimization of demodulation of said intermediate frequency digital RF receive signal. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal as recited in anyone of the accompanying patent claims. In a further aspect, the present invention provides an architecture for a multi gigaherz radio link terminal suitable for use in highly different product configurations. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal having the modulator in module M2 and the demodulator in module Ml, with the following interface features: Data to be transmitted are received in M1 and transported to M2, where modulation takes place. The received waveform in M2 is transported to M1 and is available at a suitable interface for transfer to the M1 modules of other radios. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal wherein the demodulator is equipped to receive waveforms from one or more other M1 modules to support successful demodulation. In specific configurations, obsolete functional units may be removed. In a further aspect, the present invention provides a multi gigaherz radiolink terminal intended for product portfolios covering frequencies above 3 GHz RF. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal providing communications using radio bandwidths of at least 2.5 MHz as measured in C2 or C3. In a further aspect, the present invention provides provides a high capacity multi gigaherz radio link terminal supporting communications at high data rates. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal device adapted to support products portfolios where the distance between M1 and M2 may be in the range 1 to 300 meters. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal using a cable modem to provide all communication between M1 and M2 in digital format. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal that is usable in a selection of embodiments that are flexibility to serve as a single radio, in a Space Diversity configuration, in an XPIC configuration, in a configuration with Space Diversity and XPIC, any of these connecting to either a diplexer or a branching network, and allowing High-power variants in the same mechanics. In a further aspect, the present invention provides provides a multi gigaherz radio link terminal that allows the interchange of waveforms not restricted to Space Diversity and XPIC applications. The present invention provides a method for sending a first digital data signal and receiving a second digital data signal using a multi gigahertz digital radio frequency (RF) link terminal device comprising a first outdoor unit (M2), a first indoor unit (MI), and at least one high bandwidth communications means (CS, C6) interconnecting said outdoor and indoor units, the method comprising: a) in said first indoor unit, a.1) receiving said first digital data signal at a digital data signal input (C1), modulating said first digital data signal by a modulator part (0) of a first modem to obtain a first modulated data signal,and transferring said first modulated digital data signal via said high bandwidth communications means to said outdoor unit, and a.2) receiving an intermediate frequency digital RF receive signal via said high bandwidth communications means and adapting by an first adapter means said received intermediate frequency digital RF receive signal, inputing to an RF digital demodulator (4) said adapted intermediate frequency digital RF receive signal input, demodulating by said RF digital demodulator (4) said adapted intermediate frequency digital RF receive signal to obtain said second digital data signal, and outputing on said second digital data signal on an output (C4), and b.) in said first outdoor unit: b.1) receiving and demodulating by a demodulator part (I) of said first modem means said first modulated digital data signal transferred to said indoor unit via said high bandwidth communications means to obtain said first digital data signal, generating by an RF digital modulator and multi gigahertz digital RF amplifier assembly (2) a high capacity multi gigaherz RF transmit signal and outputing said transmit signal on a multi gigahertz digital RF transmit signal output (C2), and demodualting by a demodulator part (I) of said first modem means providing an adaptation between said input of said assembly (2) and said high bandwidth communications means (CS), and b.2) receiving by a multi gigahertz digital RF receiver circuit (3) a multigigahertz digital RF receive signal and providing on an output said intermediate frequency digital RF receive signal, and adapting by a second adapter means said output of said intermediate frequency digital to said high bandwidth communications means (C6). The method of the invention further includes providing a second multi gigahertz digital radio frequency (RF) link terminal device comprising a second outdoor unit (M2')5 a second indoor unit (M1'), and at least one second high bandwidth communications means (CS', C6') interconnecting said second outdoor and indoor units, providing a connection between said RF digital demodulator (4) and a second RF digital demodulator (4') of said second second indoor unit for exchanging of RF signal demodulation processing data, said RF digital demodulator (4) of said first indoor unit having a first signal demodulation processing data input connectable to said second signal demodulation processing data output (C7), and adapting said first or second RF digital demodulator (4,4') of said first indoor unit to perform demodulation of said intermediate frequency digital RF receive signal in response to signal demodulation processing data exchanged from said second or first RF' digital demodulator (4',4), respectively. The method of the invention further includes signal handling, signal processing and signal transfer by way of an arrangement/device according to anyone of the accompanying multi gigahertz digital radio frequency (RF) link terminal device claims. Detailed description and exemplary embodiments of the invention The novel arrangement/device, having the modulator in the outdoor unit and the demodulator in the indoor unit, as shown in figure 4 and figure 5, is a prominent characteristic of the present invention. By this arrangement/device, the present invention teaches against the bias of prior art solutions which define the interface traditionally used between the indoor unit and the outdoor unit to be the only way for obtaining an efficient and attractive solution in the field of the present invention. A new interface introduced between the indoor unit and the outdoor unit would represent an additional complexity, with cost implications. Therefore, the present invention represents and identifies a solution that adds little enough cost to make the change very attractive. Furthermore, the actual interface solution that is chosen for the invention can be embodied in a number of different ways, as any interface solution that is appropriate for bringing the transmit data to the outdoor unit and the receive signal to the indoor unit within acceptable cost is considered part of an embodiment of the present invention. A first example of an interface for an employment of the invention lies in the introduction of a cable modem to transfer transmit data from the indoor unit to the outdoor unit, essentially enabling the same physical solutions for connecting the indoor unit with the outdoor unit. In the indoor unit, a new functional unit, labeled 0, is added, which modulates the digital data CI to create a cable transmit signal C5 for transfer to the outdoor unit. In the outdoor unit, the functional unit I is extended, due to the fact that demodulation has to be performed for restoring the digital data fed into the modulator, which, according to the invention is placed in close interaction with the microwave transmitter. Thus, to obtain a separation of the demodulator from the modulator in this solution, an extra cable modem has been added. By a further development of the interface solution, management communication is integrated into the modem solution for transmit data, simplifying multiplexing tasks and making previous management communication solutions obsolete. An embodiment of the present invention where the capacity of the cable modem allows transmission of a digitized version of the receive signal, is yet another attractive solution, as the need for frequency separation on the medium between the indoor unit and the outdoor unit is completely removed. Some variants of the present invention are illustrated by the accompanying, starting with the fact that the novel architecture enables the offering of a complete range of radio configurations based on the same hardware elements when technical specifications, such as frequency and output power, are kept the same. This gives major benefits in terms of development effort, logistics cost and overall manufacturing cost. The placement of the demodulator indoors enables the configuration flexibility for both simple and complex systems. Figure 6 shows a simple system solution embodiment, which embodiment by itself is not at a cost optimum. However, it offers to the customer the option to make a low-entry cost investment-with a high degree of freedom for reuse in a future expansion of the link. Figure 7 shows a more complex system embodiment, where a further radio is added to provide hardware redundancy. The freedom to reconfigure the hardware resources is high. Figure 8 shows an embodiment of the invention with a space diversity receiver radio arrangement/device. This is the first of several configurations disclosed here where the indoor placement of the demodulator proves important. The basic benefit of such a system is mitigation of selective (multipath) fading by using two antennas. In a traditional approach, the functional blocks in the transmit direction can be removed from one of the radios, including the transmission solution from M1 to M2. If a full radio is installed in both radios, it is possible to have full hardware redundancy as well, and even envision the extension to a MIMO system. Figure 9 is a schematic drawing that shows an example of a significantly more complex system embodiment of the present invention, that utilizes a common antenna for simultaneous communication at N radio channels, with one radio as a redundant hardware element. In this example, it is essential not to have the diplexer integrated with unit M2 (transceiver). Figure 10 is a schematic drawing that shows an example of an XPIC installation (cross polarization interference cancellation solution). In this example, the exchange of receive signals is used to its full extent. This solution has very high value, as it doubles the capacity within the same frequency slot. Figure 11 is a schematic drawing that shows an installation that combines Space Diversity and XPIC. It shows a system with extended use of the capability to transfer receive signals to other radios. The opportunity to be able to combine information from several receive signals is essential to meet performance requirements presented by demanding customers. For all of the exemplary radio installations illustrated by way of the figures 6 through 11, and as otherwise disclosed herein, variations for coping with conditions calling for high power variants of the transmitters in order to cope with longer hops, difficult climate etc. are contemplated. Such variants are likely to be more costly, due to, for example, the fact that the power amplifier would require the use of components that provide enhanced performance. Furthermore, it is realized by the present inventors that, if there also is a need for different mechanics, such as, for example, to cope with heat removal, the cost for the product portfolio may rise by another order of magnitude. For this reason it is extremely important to base new link terminals on the novel architecture of the present invention, in order to take advantage of the option for enhanced efficiency offered by the integrated modulator and transmitter in this new architecture. For providing efficient demodulation, and to minimise demodulation errors, the demodulators of a multi gigahertz RF terminal according to the invention is provided with an interlace for exchanging demodulation processing data related to demodulation of an intermediate RF signal being input to the modulator. The exchange of demodulation processing data can be arranged to be made in one direction from a first demodulator to a second modulator included in the same indoor unit (IDU), or as a bidirectional exchange of demodulation processing data. In case more than two demodulators are included in the same IDU, or in co-located IDUs, all of which IDUs being arranged to provide the same signal, a demodulator in one of said IDUs may be provided with an interlace for sending to, or receiving from, a plurality of said demodulators the demodulation processing data. The digital demodulator will employ appropriately designed demodulation processing, designed to take into account the information received from other demodulators to obtain the best possible demodulation result Having described preferred embodiments of multi gigahertz high capacity digital radio frequency (RF) link transceiver terminal device and method for same, it is believed that other modifications, variations and changes will be suggested to those skilled in the art in view of the teachings set forth herein. It is therefore to be understood that all such variations, modifications and changes are believed to fall within the scope of the present invention as defined by the appended claims. WE CLAIM: 1. A multi gigahertz digital radio frequency (RF) link terminal device for a digital multi gigahertz RF link, said RF terminal device comprising an indoor unit (IDU) and an outdoor unit (ODU), said IDU and ODU being physically separate from each other and interconnected by a high bandwidth communications means being adapted to carry in a transmit direction, in the form of a first digital signal, a transmit signal to be transported by said RF link and in a receive direction, in the form of first intermediate RF signals, a receive signal transported by said RF link, wherein - said ODU comprising i) a multi gigahertz RF digital modulator integrated with a multi gigahertz RF amplifier assembly, said RF digital modulator having an input adapted for accepting via high bandwidth communications means said first digital signal, and ii) at least two multi gigahertz digital RF receiver circuit assemblies being adapted for receiving a multi gigahertz digital RF receive signal and having each an output for providing via said high bandwidth communications means a respective one of said first intermediate RF signals, and said IDU having at least two RF digital demodulators having each an input adapted for accepting via said high bandwidth communications means a respective one of said first intermediate RF signals. 2. The multi gigahertz digital RF terminal device as claimed in claim 1, wherein said at least two RF digital demodulators being provided with a means for exchanging a receive signal waveform or demodulation processing data related to demodulation said respective one of said first intermediate RF signals. 3. The multi gigahertz digital RF terminal device as claimed in claim 2, wherein at least one of said at least two RF digital modulators being adapted to optimize its demodulation said respective one of said first intermediate RF signals on basis of an exchanged receive signal waveform or demodulation processing data. 4. The multi gigahertz digital RF link terminal device as claimed in claim 1, being built according to an architecture suitable for use in highly different product configurations. 5. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, having the modulator in module M2 and the demodulator in module Ml, and with the following interface features: data to be transmitted are received in MI and transported to M2, where modulation takes place; and the received waveform in M2 is transported to MI and is available at a suitable interface for transfer to the MI modules of other radios. 6. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, wherein the demodulator is equipped to receive waveforms from one or more other M1 modules to support successful demodulation, and wherein, in specific configurations, obsolete functional units may be removed. 7. The multi gigahertz digital RF link: terminal device as claimed in any one of the previous claims, being part of a product portfolios covering frequencies above 3 GHz RF. 8. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, adapted to provide communications using radio bandwidths of at least 2.5 MHz as measured in C2 or C3. 9. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, adapted to support communications at high data rates. 10. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, adapted to support a product portfolio where the distance between M1 and M2 may is in the range of 1 meter to 300 meters. 11. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, comprising a cable modem to provide all communication between M1 and M2 in digital format. 12. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, adaptable for use in a variety of embodiments providing flexibility to serve in at least one of a single radio, a Space Diversity configuration, an XPIC configuration, a configuration with Space Diversity and XPIC, and anyone of these when connected to either a diplexer or a branching network, and allowing High-power variants in the same mechanics. 13. The multi gigahertz digital RF link terminal device as claimed in any one of the previous claims, adapted to interchange of waveforms between demodulator units, said waveforms not restricted to Space Diversity and XPIC applications. 14. A multi gigahertz digital radio frequency (RF) link terminal device comprising a first outdoor unit (M2), a first indoor unit (M1), and at least one high bandwidth communications means (C5, C6) interconnecting said outdoor and indoor units, wherein - said first indoor unit comprising: a digital data signal input (C1), a modulator part (0) of a first modem means providing an adaptation between said digital data signal input and said high bandwidth communications means, an RF digital demodulator (4) having an intermediate frequency digital RF receive signal input and a digital data signal output (C4), and first adapter means providing an adaptation between said high bandwidth communications means (C6) and said intermediate frequency digital RF receive signal input, and - said first outdoor unit comprising: an RF digital modulator and multi gigahertz digital RF amplifier assembly (2), said assembly (2) having an input and a multi gigahertz digital RF transmit signal output (C2), a demodulator part (I) of said first modern means providing an adaptation between said input of said assembly (2) and said high bandwidth communications means (C5), a multi gigahertz digital RF receiver circuit (3) having a multi gigahertz digital RF receive signal input (C3) and an output for providing said intermediate frequency digital RF receive signal, and a second adapter means for providing an adaptation between said output of said multi gigahertz digital RF receiver circuit and said high bandwidth communications means (C6). 15. The multi gigahertz digital RF link terminal device as claimed in claim 14, comprising a second outdoor unit (M2'), a second indoor unit (M1'), and a second high bandwidth communications means (C6') interconnecting said second outdoor and second indoor units, wherein - said second indoor unit comprising: an RF digital demodulator (4) having a second intermediate frequency digital RF receive signal input and a second signal demodulation processing data output (C7), and a third adapter means providing an adaptation between said second high bandwidth communications means (C6') and said second intermediate frequency digital RF receive signal input, and - said outdoor unit comprising: a second multi gigahertz digital RF receiver circuit (3') having a second multi gigahertz digital RF receive signal input (C3') and an second output for providing said second intermediate frequency digital RF receive signal, and a fourth adapter means for providing an adaptation between said second output of said multi gigahertz digital RF receiver circuit and said second high bandwidth communications means (C6'). 16. The multi gigahertz digital RF link terminal device as claimed in claim 15, wherein said RF digital demodulator (4) of said first indoor unit having a first signal demodulation processing data input connectable to said second signal demodulation processing data output (C7), and said RF digital demodulator (4) of said first indoor unit being adapted to perform demodulation of said intermediate frequency digital RF receive signal in response to said second signal demodulation processing data. 17. The multi gigahertz digital RF link terminal device as claimed in claim 15 or 16, wherein said RF digital demodulator (4) of said first indoor unit having a first signal demodulation processing data output (C8), said second RF digital demodulator (4') of said second indoor unit having a second signal demodulation processing data input connectable to said first signal demodulation processing data output (C8), and said second RF digital demodulator (4') being adapted to perform demodulation of said second intermediate frequency digital RF receive signal in response to said first signal demodulation processing data. 18. A method for sending a first digital data signal and receiving a second digital data signal using a multi gigahertz digital radio frequency (RF) link terminal device comprising a first outdoor unit (M2), a first indoor unit (M1), and at least one high bandwidth communications means (C5, C6) interconnecting said outdoor and indoor units, the method comprising: a) in said first indoor unit, a.1) receiving said first digital data signal at a digital data signal input (C1), modulating said first digital data signal by a modulator part (0) of a first modem to obtain a first modulated digital data signal, and transferring said first modulated digital data signal via said high bandwidth communications means to said outdoor unit, and a.2) receiving an intermediate frequency digital RF receive signal via said high bandwidth communications means and adapting by an first adapter means said received intermediate frequency digital RF receive signal, inputing to an RF digital demodulator (4) said adapted intermediate frequency digital RF receive signal input, demodulating by said RF digital demodulator (4) said adapted intermediate frequency digital RF receive signal to obtain said second digital data signal, and outputing on said second digital data signal on an output (C4), and b.) in said first outdoor unit: b.1) receiving and demodulating by a demodulator part (1) of said first modem means said first modulated digital data signal transferred to said indoor unit via said high bandwidth communications means to obtain said first digital data signal, generating by an RF digital modulator and multi gigahertz digital RF amplifier assembly (2) a high capacity multi gigaherz RF transmit signal and outputing said transmit signal on a multi gigahertz digital RF transmit signal output (Cz), and demodualting by a demodulator part (1) of said first modem means providing an adaptation between said input of said assembly (2) and said high bandwidth communications means (C5), and b.2) receiving by a multi gigahertz digital RF receiver circuit (3) a multi gigahertz digital RF receive signal and providing on an output said intermediate frequency digital RF receive signal, and adapting by a second adapter means said output of said intermediate frequency digital to said high bandwidth communications means (C6). 19. The method as claimed in claim 18, involving providing a second multi gigahertz digital radio frequency (RF) link terminal device comprising a second outdoor unit (M2'), a second indoor unit (M1'), and at least one second high bandwidth communications means (C5', C6') interconnecting said second outdoor and indoor units, providing a connection between said RF digital demodulator (4) and a second RF digital demodulator (4') of said second second indoor unit for exchanging a receive signal waveform or signal demodulation processing data, said RF digital demodulator (4) of said first indoor unit having a first signal demodulation processing data input connectable to said second signal demodulation processing data output (C7), and adapting said first or second RF digital demodulator (4,4') of said first indoor unit to perform demodulation of said intermediate frequency digital RF receive signal in response to signal demodulation processing data exchanged from said second or first RF digital demodulator (4',4), respectively. 20. The method as claimed in claim 18 or 19, involving signal handling, signal processing and signal transfer by way of a multi gigahertz digital RF terminal device as claimed in any one of claims 1 to 17. ABSTRACT A MULTI GIGAHERTZ HIGH CAPACITY DIGITAL RADIO FREQUENCY (RF) LINK TRANSCEIVER TERMINAL DEVICE, AND METHOD FOR SAME A multi gigahertz digital radio frequency (RF) link terminal device is disclosed. The device comprises an indoor unit and an outdoors connected by at least one high bandwidth communications means adapted to carry in a transmit direction a digital signal to be transported by said radiolink and in a receive direction an intermediate frequency digital RF receive signal to be transported by clink. The outdoor unit includes an RF digital modulator integrated with a multi gigahertz digital RF amplifier assembly and at least two multi gigahertz digital RF receiver circuit assemblies, each having a multi gigahertz digital RF receive signal input and outputs for providing a respective one of a intermediate frequency digital RF receive signal. The indoor unit includes at least two RF digital demodulators having each an input for receiving at least one of the intermediate frequency digital RF receive signals, and said at least two RF digital demodulators being adapted to exchange signal demodulation processing data to allow mutual optimization of demodulation of said- intermediate frequency digital RF receive signal.

Full Text

Field of invention
The present invention relates to a multi gigahertz high capacity digital radio frequency (RF)
link transceiver terminal device, and method for same. The field of application for the present
invention may generally be labelled "high capacity microwave radio", and more specifically
such kind of microwave radio link solutions that offer very high quality, very high reliability,
point-to-point or point-to-multipoint communication with capacities beyond 8Mb/s wireless
communication at microwave frequencies. In the context of the present invention, microwave
frequencies are understood to include the range 3GHz to 100GHz.
The field of interest is in particular described in terms of the variability and complexity of the
possible installations, ranging from single channel solutions without interaction with other
radios to more complex installations requiring access to more than one receive signal for
successful operation. Application like MIMO systems (Multiple Input, Multiple Output) and
future interference mitigation solutions are considered to be of relevance to the present
invention.
Known solutions and problems with these
High capacity radio systems serve a variety of communication needs, and the great range of
potential applications makes it natural to explain this invention in the light of technology and
logistics, reflecting the kind of problem it aims to solve. The traditional applications are
described by Freeman, Roger L., "Radio System Design for Telecommunications", Second
Edition (New York: John Wiley & Sons, 1997), giving an introduction to the application
background for the invention.
Norwegian patent application no 20034776, filed 24. Oct. 2003

When making radio systems for trunk and mobile backhaul point-to point communication, it
turns out that the conventional arrangement/device of the functional units does not allow
exploitation of technology advances for efficient radio transmitters. Point-to point high
capacity radios operate at high frequencies, traditionally requiring line-of sight between the
two antennas. The antennas often have to be placed in towers or other inconvenient locations
with respect to access and maintenance. It is often highly desirable to have the transmit power
amplifier as close to the antenna as possible in order to avoid power loss. For the same reason
it is desirable to have the receive low noise amplifier close to the antenna.
The split of radio installations into an outdoor unit and an indoor unit is natural. The outdoor
unit should be robust and as simple as possible, and if one can afford the losses by separating
the antenna from the transmit power amplifier and the receiver low noise amplifier, we may
find that only the antenna belongs to the outdoor unit For solutions in a product portfolio
where this is not always the case, it has become common to designate all functional units that
may need to be located outdoors in some installations as outdoor functions. As we only need
to have channel frequency specific hardware in the outdoor functions, it has become common
practice to class all channel frequency dependant hardware as outdoor functions, assuming
communication with functions in the indoor unit at one or more fixed frequencies. The
importance of this interface solution is shown by the fact that the outdoor unit actually
includes the functional units on the antenna side of the abovementioned fixed frequency
interface, regardless of whether these functional units are placed indoors or outdoors,
meaning that what is typically referred to as the outdoor unit can in fact be distributed as, for
example, an outdoor antenna and an indoor transceiver. Likewise would all functional units
separated from the antenna by the abovementioned fixed frequency interface belong to the
indoor unit.
This fixed, typically intermediate frequency interface between the outdoor unit and the indoor
unit enables a standardization that makes the indoor unit hardware frequency independent.
The implementation also is very effective. In the outdoor unit one only needs to shift the
frequencies between the specific radio channels and the selected intermediate frequencies.

The modulator and the demodulator of the indoor unit are not more costly due to the extra
frequency conversion. Adding management messages and power supply to the same cable
effectively completes a general interface allowing very flexible product arrangements
devices.
An illustration of this basic arrangement/device is provided in figure 1, giving the opportunity
to define some terminology useful for the following descriptions. At the far right, an antenna
is indicated in location A, closely connected to a frequency separation solution, marked D.
The frequency separation solution can be a diplexer or more complex branching
arrangements/devices. The signal prepared for wireless transmission, C2, and the received
signal, C3, from the antenna are identified here. To the left of the frequency separation
solution (D), we find two functional units, numbered 2 and 3, and collectively labeled M2 as
an abbreviation for "module 2", often named a transceiver.
Functional unit 2 performs frequency translation and amplification of the transmit signal,
while functional unit 3 performs low-noise amplification and frequency translation of the
receive signal. The outdoor unit hence contains the units labeled A, D and M2. The functional
units 2 and 3 are kept together in a common module because they represent units that are
most likely to need service in the outdoor unit, and efforts have been made to ease
replacement service by non-specialists. Depending on product, M2 and D may be integrated
as well.
The module M1 is 'part of the indoor unit of the radio system, containing the modulator unit 1
and the demodulator unit 4 for the specific radio. The interface towards the outdoor unit is as
described above. We identify the transmit signal, C5, and the received signal, C6, both having
chosen,fixed frequencies. A cable based connection, covering distances from 1 to 300 meters
between M1 and M2 provides an effective communication solution. Input digital data for
wireless transmission, labeled C1, are received in the modulator unit 1. Output digital data,
demodulated from the received signal, are provided from the demodulator 4, at the interface
labeled C4.

There is significant cost associated with the generation of the transmit signal with required
quality. Recent developments, such as what is disclosed in Norwegian patent application no
20034776, filed by the present applicant on 24. Oct. 2003, have created further potential for
improvement in the transmit chain, having an important impact on system cost, output power,
linearity and efficiency of the power amplifier. To take full advantage of these advancements,
the modulator unit 1 and the circuits at channel frequency, including the power amplifier,must
work in close cooperation, which in turn requires physical proximity. Known arrangements/
devices (radio architectures) are not capable of taking full advantage of such solutions due to
the physical distances that traditionally separate the indoor unit from the outdoor unit, which
may be as large as up to 300 meters. Until now, the skilled person in the art has chosen the
obvious solution to this problem, namely to move both modulator and demodulator to the
outdoor unit, thereby eliminating the interfaces at C5 and C6. Thus, by communication of the
input data and the output data at C1 and C4, respectively, directly to the outdoor unit, as
known from in present day technology, a straightforward solution is available. This
straightforward solution, however, does not address the thereby incurred problems of
maintainability and other important operational aspects, which all tend to add cost and other
design considerations in order to meet the stringent performance requirements that typically
are presented by radio link operators.
Furthermore, in installations with more than one radio channel, quality and availability
requirements, in conjunction with the desire to utilize the spectrum as efficiently as possible,
often require the demodulators to cooperate. One example of this is the use of two, or even
more, polarizations in a radio link. Briefly, the antennas are arranged to excite and receive
signals at, for example, orthogonal polarizations, thereby multiplying the spectrum utilization.
However, in the case of orthogonal polarization, perfect orthogonality is a rare event, and
there is need for interference mitigation in order to arrive at the expected performance. If a
demodulator receives the signal from both polarizations, it is possible to solve this task. The
traditional solution to this is illustrated in figure 2, being characterized by the need to
exchange the received signal between the two demodulators. This transfer of received signals

is labeled C7. Other arrangements/devices exist, requiring similar transfers of signals, giving
cross connections similar to what is shown in figure 3. One or more antennas may be used.
The essential feature is that some of the demodulators need access to the receive signals from
one or more other receivers.
If the demodulators are placed in respective outdoor units for such system arrangements/
devices, then cross-links between the demodulators outdoors must to be provided. It is clear
that such an arrangement/device will incur significant costs.
To date, the industry has tried to improve the transmit chain cost and performance for
complex radio installations without taking advantage of the potential associated with close
connection between the modulator and channel frequency dependant hardware, including the
power amplifier. The inventors of the present invention do not know of any previously known
solution to this challenge of the type disclosed herein.
Brief description and objects of the invention
According to the present invention, it is proposed to separate the modulator and demodulator
units, whereby it becomes possible to take advantage of benefits in the transmit chain while
maintaining the advantages of having an indoor demodulator. The idea of such a separation
results in some complications to be overcome. The choice to do so and the measures taken to
overcome the associated obstacles are material to the invention.
The major benefits become apparent when a complete product portfolio is to be created that
supports a variety system solutions that range from from single channel radios with just one
transmitter and one receiver to complex systems that for performing one or more
demodulation tasks require access to more than one of the received radio signals. The typical
solution of optimised hardware for the different configurations is not a viable alternative, as
customers often want flexibility and options for further expansion, and because the average
number of installations per configuration typically is limited.

In order to arrive at a solution that enables a common hardware platform to support all
configurations of interest in a cost effective manner, it is an important choice not to integrate
the frequency separating unit with the module M2, as seen in figure 4 and figure 5, where the
transmit and receive signals are simply labelled C2 and C3. This enables assembly of simple,
diplexer based, installations using the same modules as those employed in more complex
solutions that are based on branching.
A further object of the invention is to take advantage of a common mechanical solution. Such
a solution must cope with all product configurations, including variants with high output
power that may have demanding thermal requirements. Exploitation of the integrated
transmit chain and the solution disclosed in Norwegian patent application no 20034776, filed
24. Oct. 2003, to obtain maximum power efficiency by means of e.g. dynamic biasing
schemes in installations requiring high output power, eases the thermal requirements
significantly. In the context of the present invention, this new technology further enhances the
enablement of one common mechanical solution for a complete product range that does not
add what previously has been considered unacceptable cost.
In a first aspect, the present invention provides a multi gigahertz digital radio frequency (RF)
link terminal device comprising an indoor unit and an outdoor unit interconnected by at least
one high bandwidth communications means for carrying in a transmit direction a digital
signal to be transported by said radiolink and in a receive direction an intermediate frequency
digital RF receive signal to be transported by said radiolink. The outdoor unit includes an RF
digital modulator integrated with a multi gigahertz digital RF amplifier assembly, said RF
digital modulator having an input adapted for receiving said digital signal to be transmitted by
said radiolink, and at least two multi gigahertz digital RF receiver circuit assemblies adapted
for receiving a multi gigahertz digital RF receive signal and having an output each for
providing a respective one of said intermediate frequency digital RF receive signal. The
indoor unit including at least two RF digital demodulators having each an input adapted for
receiving at least one of said respective one of said intermediate frequency digital RF receive

signal. The at least two RF digital demodulators are provided with a means for exchanging
signal demodulation processing data to allow mutual optimization of demodulation of said
intermediate frequency digital RF receive signal.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal as recited in anyone of the accompanying patent claims.
In a further aspect, the present invention provides an architecture for a multi gigaherz radio
link terminal suitable for use in highly different product configurations.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal having the modulator in module M2 and the demodulator in module Ml, with the
following interface features: Data to be transmitted are received in M1 and transported to M2,
where modulation takes place. The received waveform in M2 is transported to M1 and is
available at a suitable interface for transfer to the M1 modules of other radios.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal wherein the demodulator is equipped to receive waveforms from one or more other
M1 modules to support successful demodulation. In specific configurations, obsolete
functional units may be removed.
In a further aspect, the present invention provides a multi gigaherz radiolink terminal intended
for product portfolios covering frequencies above 3 GHz RF.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal providing communications using radio bandwidths of at least 2.5 MHz as measured
in C2 or C3.
In a further aspect, the present invention provides provides a high capacity multi gigaherz
radio link terminal supporting communications at high data rates.

In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal device adapted to support products portfolios where the distance between M1 and
M2 may be in the range 1 to 300 meters.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal using a cable modem to provide all communication between M1 and M2 in digital
format.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal that is usable in a selection of embodiments that are flexibility to serve as a single
radio, in a Space Diversity configuration, in an XPIC configuration, in a configuration with
Space Diversity and XPIC, any of these connecting to either a diplexer or a branching
network, and allowing High-power variants in the same mechanics.
In a further aspect, the present invention provides provides a multi gigaherz radio link
terminal that allows the interchange of waveforms not restricted to Space Diversity and XPIC
applications.
The present invention provides a method for sending a first digital data signal and receiving a
second digital data signal using a multi gigahertz digital radio frequency (RF) link terminal
device comprising a first outdoor unit (M2), a first indoor unit (MI), and at least one high
bandwidth communications means (CS, C6) interconnecting said outdoor and indoor units,
the method comprising:
a) in said first indoor unit,
a.1) receiving said first digital data signal at a digital data signal input (C1),
modulating said first digital data signal by a modulator part (0) of a first modem to obtain a
first modulated data signal,and transferring said first modulated digital data signal via said
high bandwidth communications means to said outdoor unit, and
a.2) receiving an intermediate frequency digital RF receive signal via said high

bandwidth communications means and adapting by an first adapter means said received
intermediate frequency digital RF receive signal, inputing to an RF digital demodulator (4)
said adapted intermediate frequency digital RF receive signal input, demodulating by said RF
digital demodulator (4) said adapted intermediate frequency digital RF receive signal to
obtain said second digital data signal, and outputing on said second digital data signal on an
output (C4), and
b.) in said first outdoor unit:
b.1) receiving and demodulating by a demodulator part (I) of said first modem means
said first modulated digital data signal transferred to said indoor unit via said high bandwidth
communications means to obtain said first digital data signal, generating by an RF digital
modulator and multi gigahertz digital RF amplifier assembly (2) a high capacity multi
gigaherz RF transmit signal and outputing said transmit signal on a multi gigahertz digital RF
transmit signal output (C2), and demodualting by a demodulator part (I) of said first modem
means providing an adaptation between said input of said assembly (2) and said high
bandwidth communications means (CS), and
b.2) receiving by a multi gigahertz digital RF receiver circuit (3) a multigigahertz
digital RF receive signal and providing on an output said intermediate frequency digital RF
receive signal, and adapting by a second adapter means said output of said intermediate
frequency digital to said high bandwidth communications means (C6).
The method of the invention further includes providing a second multi gigahertz digital radio
frequency (RF) link terminal device comprising a second outdoor unit (M2')5 a second indoor
unit (M1'), and at least one second high bandwidth communications means (CS', C6')
interconnecting said second outdoor and indoor units,
providing a connection between said RF digital demodulator (4) and a second RF
digital demodulator (4') of said second second indoor unit for exchanging of RF signal
demodulation processing data,
said RF digital demodulator (4) of said first indoor unit having a first signal
demodulation processing data input connectable to said second signal demodulation
processing data output (C7), and

adapting said first or second RF digital demodulator (4,4') of said first indoor unit to
perform demodulation of said intermediate frequency digital RF receive signal in response to
signal demodulation processing data exchanged from said second or first RF' digital
demodulator (4',4), respectively.
The method of the invention further includes signal handling, signal processing and signal
transfer by way of an arrangement/device according to anyone of the accompanying multi
gigahertz digital radio frequency (RF) link terminal device claims.
Detailed description and exemplary embodiments of the invention
The novel arrangement/device, having the modulator in the outdoor unit and the demodulator
in the indoor unit, as shown in figure 4 and figure 5, is a prominent characteristic of the
present invention. By this arrangement/device, the present invention teaches against the bias
of prior art solutions which define the interface traditionally used between the indoor unit and
the outdoor unit to be the only way for obtaining an efficient and attractive solution in the
field of the present invention.
A new interface introduced between the indoor unit and the outdoor unit would represent an
additional complexity, with cost implications. Therefore, the present invention represents and
identifies a solution that adds little enough cost to make the change very attractive.
Furthermore, the actual interface solution that is chosen for the invention can be embodied in
a number of different ways, as any interface solution that is appropriate for bringing the
transmit data to the outdoor unit and the receive signal to the indoor unit within acceptable
cost is considered part of an embodiment of the present invention.
A first example of an interface for an employment of the invention lies in the introduction of a
cable modem to transfer transmit data from the indoor unit to the outdoor unit, essentially
enabling the same physical solutions for connecting the indoor unit with the outdoor unit. In
the indoor unit, a new functional unit, labeled 0, is added, which modulates the digital data CI

to create a cable transmit signal C5 for transfer to the outdoor unit. In the outdoor unit, the
functional unit I is extended, due to the fact that demodulation has to be performed for
restoring the digital data fed into the modulator, which, according to the invention is placed in
close interaction with the microwave transmitter. Thus, to obtain a separation of the
demodulator from the modulator in this solution, an extra cable modem has been added.
By a further development of the interface solution, management communication is integrated
into the modem solution for transmit data, simplifying multiplexing tasks and making
previous management communication solutions obsolete.
An embodiment of the present invention where the capacity of the cable modem allows
transmission of a digitized version of the receive signal, is yet another attractive solution, as
the need for frequency separation on the medium between the indoor unit and the outdoor unit
is completely removed.
Some variants of the present invention are illustrated by the accompanying, starting with the
fact that the novel architecture enables the offering of a complete range of radio
configurations based on the same hardware elements when technical specifications, such as
frequency and output power, are kept the same. This gives major benefits in terms of
development effort, logistics cost and overall manufacturing cost.
The placement of the demodulator indoors enables the configuration flexibility for both
simple and complex systems.
Figure 6 shows a simple system solution embodiment, which embodiment by itself is not at a
cost optimum. However, it offers to the customer the option to make a low-entry cost
investment-with a high degree of freedom for reuse in a future expansion of the link.
Figure 7 shows a more complex system embodiment, where a further radio is added to
provide hardware redundancy. The freedom to reconfigure the hardware resources is high.

Figure 8 shows an embodiment of the invention with a space diversity receiver radio
arrangement/device. This is the first of several configurations disclosed here where the indoor
placement of the demodulator proves important. The basic benefit of such a system is
mitigation of selective (multipath) fading by using two antennas.
In a traditional approach, the functional blocks in the transmit direction can be removed from
one of the radios, including the transmission solution from M1 to M2. If a full radio is
installed in both radios, it is possible to have full hardware redundancy as well, and even
envision the extension to a MIMO system.
Figure 9 is a schematic drawing that shows an example of a significantly more complex
system embodiment of the present invention, that utilizes a common antenna for simultaneous
communication at N radio channels, with one radio as a redundant hardware element. In this
example, it is essential not to have the diplexer integrated with unit M2 (transceiver).
Figure 10 is a schematic drawing that shows an example of an XPIC installation (cross
polarization interference cancellation solution). In this example, the exchange of receive
signals is used to its full extent. This solution has very high value, as it doubles the capacity
within the same frequency slot.
Figure 11 is a schematic drawing that shows an installation that combines Space Diversity
and XPIC. It shows a system with extended use of the capability to transfer receive signals to
other radios. The opportunity to be able to combine information from several receive signals
is essential to meet performance requirements presented by demanding customers.
For all of the exemplary radio installations illustrated by way of the figures 6 through 11, and
as otherwise disclosed herein, variations for coping with conditions calling for high power
variants of the transmitters in order to cope with longer hops, difficult climate etc. are
contemplated. Such variants are likely to be more costly, due to, for example, the fact that the

power amplifier would require the use of components that provide enhanced performance.
Furthermore, it is realized by the present inventors that, if there also is a need for different
mechanics, such as, for example, to cope with heat removal, the cost for the product portfolio
may rise by another order of magnitude. For this reason it is extremely important to base new
link terminals on the novel architecture of the present invention, in order to take advantage of
the option for enhanced efficiency offered by the integrated modulator and transmitter in this
new architecture.
For providing efficient demodulation, and to minimise demodulation errors, the demodulators
of a multi gigahertz RF terminal according to the invention is provided with an interlace for
exchanging demodulation processing data related to demodulation of an intermediate RF
signal being input to the modulator. The exchange of demodulation processing data can be
arranged to be made in one direction from a first demodulator to a second modulator included
in the same indoor unit (IDU), or as a bidirectional exchange of demodulation processing
data. In case more than two demodulators are included in the same IDU, or in co-located
IDUs, all of which IDUs being arranged to provide the same signal, a demodulator in one of
said IDUs may be provided with an interlace for sending to, or receiving from, a plurality of
said demodulators the demodulation processing data. The digital demodulator will employ
appropriately designed demodulation processing, designed to take into account the
information received from other demodulators to obtain the best possible demodulation result
Having described preferred embodiments of multi gigahertz high capacity digital radio
frequency (RF) link transceiver terminal device and method for same, it is believed that other
modifications, variations and changes will be suggested to those skilled in the art in view of
the teachings set forth herein. It is therefore to be understood that all such variations,
modifications and changes are believed to fall within the scope of the present invention as
defined by the appended claims.

WE CLAIM:
1. A multi gigahertz digital radio frequency (RF) link terminal device for a digital multi
gigahertz RF link, said RF terminal device comprising an indoor unit (IDU) and an outdoor
unit (ODU), said IDU and ODU being physically separate from each other and interconnected
by a high bandwidth communications means being adapted to carry in a transmit direction, in
the form of a first digital signal, a transmit signal to be transported by said RF link and in a
receive direction, in the form of first intermediate RF signals, a receive signal transported by
said RF link, wherein - said ODU comprising
i) a multi gigahertz RF digital modulator integrated with a multi gigahertz RF
amplifier assembly, said RF digital modulator having an input adapted for accepting via high
bandwidth communications means said first digital signal, and
ii) at least two multi gigahertz digital RF receiver circuit assemblies being
adapted for receiving a multi gigahertz digital RF receive signal and having each an output
for providing via said high bandwidth communications means a respective one of said first
intermediate RF signals, and
said IDU having at least two RF digital demodulators having each an input
adapted for accepting via said high bandwidth communications means a respective one of
said first intermediate RF signals.
2. The multi gigahertz digital RF terminal device as claimed in claim 1, wherein said at
least two RF digital demodulators being provided with a means for exchanging a receive
signal waveform or demodulation processing data related to demodulation said respective one
of said first intermediate RF signals.
3. The multi gigahertz digital RF terminal device as claimed in claim 2, wherein at least
one of said at least two RF digital modulators being adapted to optimize its demodulation said
respective one of said first intermediate RF signals on basis of an exchanged receive signal
waveform or demodulation processing data.

4. The multi gigahertz digital RF link terminal device as claimed in claim 1, being built
according to an architecture suitable for use in highly different product configurations.
5. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, having the modulator in module M2 and the demodulator in module Ml, and
with the following interface features:
data to be transmitted are received in MI and transported to M2, where
modulation takes place; and
the received waveform in M2 is transported to MI and is available at a suitable
interface for transfer to the MI modules of other radios.
6. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, wherein the demodulator is equipped to receive waveforms from one or
more other M1 modules to support successful demodulation, and
wherein, in specific configurations, obsolete functional units may be removed.
7. The multi gigahertz digital RF link: terminal device as claimed in any one of the
previous claims, being part of a product portfolios covering frequencies above 3 GHz RF.
8. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, adapted to provide communications using radio bandwidths of at least 2.5
MHz as measured in C2 or C3.
9. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, adapted to support communications at high data rates.
10. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, adapted to support a product portfolio where the distance between M1 and
M2 may is in the range of 1 meter to 300 meters.

11. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, comprising a cable modem to provide all communication between M1 and
M2 in digital format.
12. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, adaptable for use in a variety of embodiments providing flexibility to serve
in at least one of a single radio, a Space Diversity configuration, an XPIC configuration, a
configuration with Space Diversity and XPIC, and anyone of these when connected to either a
diplexer or a branching network, and allowing High-power variants in the same mechanics.
13. The multi gigahertz digital RF link terminal device as claimed in any one of the
previous claims, adapted to interchange of waveforms between demodulator units, said
waveforms not restricted to Space Diversity and XPIC applications.
14. A multi gigahertz digital radio frequency (RF) link terminal device comprising a first
outdoor unit (M2), a first indoor unit (M1), and at least one high bandwidth communications
means (C5, C6) interconnecting said outdoor and indoor units, wherein
- said first indoor unit comprising:
a digital data signal input (C1),
a modulator part (0) of a first modem means providing an adaptation between said
digital data signal input and said high bandwidth communications means,
an RF digital demodulator (4) having an intermediate frequency digital RF receive
signal input and a digital data signal output (C4),
and first adapter means providing an adaptation between said high bandwidth
communications means (C6) and said intermediate frequency digital RF receive signal input,
and
- said first outdoor unit comprising:
an RF digital modulator and multi gigahertz digital RF amplifier assembly (2), said
assembly (2) having an input and a multi gigahertz digital RF transmit signal output (C2),

a demodulator part (I) of said first modern means providing an adaptation between
said input of said assembly (2) and said high bandwidth communications means (C5),
a multi gigahertz digital RF receiver circuit (3) having a multi gigahertz digital RF
receive signal input (C3) and an output for providing said intermediate frequency digital RF
receive signal, and
a second adapter means for providing an adaptation between said output of said multi
gigahertz digital RF receiver circuit and said high bandwidth communications means (C6).
15. The multi gigahertz digital RF link terminal device as claimed in claim 14, comprising
a second outdoor unit (M2'), a second indoor unit (M1'), and a second high bandwidth
communications means (C6') interconnecting said second outdoor and second indoor units,
wherein
- said second indoor unit comprising:
an RF digital demodulator (4) having a second intermediate frequency digital RF
receive signal input and a second signal demodulation processing data output (C7), and a
third adapter means providing an adaptation between said second high bandwidth
communications means (C6') and said second intermediate frequency digital RF receive
signal input, and
- said outdoor unit comprising:
a second multi gigahertz digital RF receiver circuit (3') having a second multi
gigahertz digital RF receive signal input (C3') and an second output for providing said second
intermediate frequency digital RF receive signal, and
a fourth adapter means for providing an adaptation between said second output of said
multi gigahertz digital RF receiver circuit and said second high bandwidth
communications means (C6').
16. The multi gigahertz digital RF link terminal device as claimed in claim 15, wherein
said RF digital demodulator (4) of said first indoor unit having a first signal demodulation
processing data input connectable to said second signal demodulation processing data output
(C7), and

said RF digital demodulator (4) of said first indoor unit being adapted to perform
demodulation of said intermediate frequency digital RF receive signal in response to said
second signal demodulation processing data.
17. The multi gigahertz digital RF link terminal device as claimed in claim 15 or 16,
wherein said RF digital demodulator (4) of said first indoor unit having a first signal
demodulation processing data output (C8),
said second RF digital demodulator (4') of said second indoor unit having a second
signal demodulation processing data input connectable to said first signal demodulation
processing data output (C8), and
said second RF digital demodulator (4') being adapted to perform demodulation of
said second intermediate frequency digital RF receive signal in response to said first signal
demodulation processing data.
18. A method for sending a first digital data signal and receiving a second digital data
signal using a multi gigahertz digital radio frequency (RF) link terminal device comprising a
first outdoor unit (M2), a first indoor unit (M1), and at least one high bandwidth
communications means (C5, C6) interconnecting said outdoor and indoor units, the method
comprising:
a) in said first indoor unit,
a.1) receiving said first digital data signal at a digital data signal input (C1),
modulating said first digital data signal by a modulator part (0) of a first modem to obtain a
first modulated digital data signal, and transferring said first modulated digital data signal via
said high bandwidth communications means to said outdoor unit, and
a.2) receiving an intermediate frequency digital RF receive signal via said high
bandwidth communications means and adapting by an first adapter means said received
intermediate frequency digital RF receive signal, inputing to an RF digital demodulator (4)
said adapted intermediate frequency digital RF receive signal input, demodulating by said RF
digital demodulator (4) said adapted intermediate frequency digital RF receive signal to
obtain said second digital data signal, and outputing on said second digital data signal on an

output (C4), and
b.) in said first outdoor unit:
b.1) receiving and demodulating by a demodulator part (1) of said first modem
means said first modulated digital data signal transferred to said indoor unit via said high
bandwidth communications means to obtain said first digital data signal,
generating by an RF digital modulator and multi gigahertz digital RF amplifier
assembly (2) a high capacity multi gigaherz RF transmit signal and outputing said transmit
signal on a multi gigahertz digital RF transmit signal output (Cz),
and demodualting by a demodulator part (1) of said first modem means providing an
adaptation between said input of said assembly (2) and said high bandwidth communications
means (C5), and
b.2) receiving by a multi gigahertz digital RF receiver circuit (3) a multi gigahertz
digital RF receive signal and providing on an output said intermediate frequency digital RF
receive signal, and adapting by a second adapter means said output of said intermediate
frequency digital to said high bandwidth communications means (C6).
19. The method as claimed in claim 18, involving providing a second multi gigahertz
digital radio frequency (RF) link terminal device comprising a second outdoor unit (M2'), a
second indoor unit (M1'), and at least one second high bandwidth communications means
(C5', C6') interconnecting said second outdoor and indoor units,
providing a connection between said RF digital demodulator (4) and a second RF
digital demodulator (4') of said second second indoor unit for exchanging a receive signal
waveform or signal demodulation processing data,
said RF digital demodulator (4) of said first indoor unit having a first signal
demodulation processing data input connectable to said second signal demodulation
processing data output (C7), and
adapting said first or second RF digital demodulator (4,4') of said first indoor unit to
perform demodulation of said intermediate frequency digital RF receive signal in response to
signal demodulation processing data exchanged from said second or first RF digital
demodulator (4',4), respectively.

20. The method as claimed in claim 18 or 19, involving signal handling, signal processing
and signal transfer by way of a multi gigahertz digital RF terminal device as claimed in any
one of claims 1 to 17.

ABSTRACT

A MULTI GIGAHERTZ HIGH CAPACITY DIGITAL RADIO FREQUENCY (RF)
LINK TRANSCEIVER TERMINAL DEVICE, AND METHOD FOR SAME
A multi gigahertz digital radio frequency (RF) link terminal device is disclosed. The
device comprises an indoor unit and an outdoors connected by at least one high bandwidth
communications means adapted to carry in a transmit direction a digital signal to be
transported by said radiolink and in a receive direction an intermediate frequency digital RF
receive signal to be transported by clink. The outdoor unit includes an RF digital modulator
integrated with a multi gigahertz digital RF amplifier assembly and at least two multi
gigahertz digital RF receiver circuit assemblies, each having a multi gigahertz digital RF
receive signal input and outputs for providing a respective one of a intermediate frequency
digital RF receive signal. The indoor unit includes at least two RF digital demodulators
having each an input for receiving at least one of the intermediate frequency digital RF
receive signals, and said at least two RF digital demodulators being adapted to exchange
signal demodulation processing data to allow mutual optimization of demodulation of said-
intermediate frequency digital RF receive signal.

A MULTI GIGAHERTZ HIGH CAPACITY DIGITAL RADIO FREQUENCY (RF) LINK TRANSCEIVER TERMINAL DEVICE AND METHOD FOR SAME

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