Receiver unit for microwave link site

Abstract

There is provided techniques for processing signals by a receiver unit of a microwave link site. A method comprises processing, by an analog processing circuitry, an analog signal as received over the air by an antenna of the microwave link site. The method comprises converting, by an analog-to-digital converter, the analog signal, as processed by the analog processing circuitry, to a first digital signal. The method comprises sending, by a digital signal interface, the first digital signal to at least one further receiver unit of the microwave link site over a digital connection. The method comprises receiving, by the digital signal interface, a respective second digital signal from each of said at least one further receiver unit over the digital connection. The method comprises processing, by a digital processing unit, the first digital signal and said respective second digital signal.

Description

[0001] RECEIVER UNIT FOR MICROWAVE LINK SITE

[0002] TECHNICAL FIELD

[0003] Embodiments presented herein relate to a method, a receiver unit, a computer program, and a computer program product for processing signals by a receiver unit of a microwave link site.

[0004] BACKGROUND

[0005] In general terms, a Multiple-Input Multiple-Output (MIMO) microwave system is an example of a wireless communication technology that utilizes multiple transmitting and receiving antennas to improve signal quality, capacity, and reliability in high-frequency microwave transmissions. MIMO microwave systems are widely used in telecommunications infrastructure, especially for backhaul links that connect base stations to the core network. They are also employed in point-to-point and point-to-multipoint communications, providing high-capacity, high-reliability links for mobile operators, internet service providers, and enterprise networks.

[0006] In traditional microwave systems, signals are transmitted and received using a single antenna at each end of the communication link. In a MIMO microwave system, however, multiple antennas are employed at both the transmitter and the receiver. These antennas work together to create multiple independent signal paths, effectively increasing system capacity without requiring additional bandwidth or power.

[0007] Each signal path created between a transmitting and receiving antenna pair can be referred to as a spatial stream. In a MIMO microwave system, multiple spatial streams can be transmitted simultaneously, which significantly increases data throughput. For example, a 2-by-2 MIMO microwave system has two transmitters and two receivers, offering two spatial streams. More advanced MIMO microwave systems may support 4-by-4, 8-by-8, or even higher configurations, leading to even greater capacity and robustness.

[0008] A non-limiting example of a line-of-sight 2-by-2 MIMO microwave system 100 is illustrated in Fig. 1. The line-of-sight 2-by-2 MIMO microwave system 100 comprises a split-mount transmitter arrangement 110a and a split-mount receiver arrangement 110b. In turn, the split-mount transmitter arrangement 110a comprises two transmitter antennas 120a, 120b mounted high up on a first mast, and the split-mount receiver arrangement 110b comprises two receiver antennas 130a, 130b mounted high up on a second mast. The antennas are placed at fixed positions, aiming at producing a 90 degree phase shift between the spatial streams (as schematically indicated by dotted lines) transmitted from the two transmitter antennas 120a, 120b at each of the two receiver antennas 130a, 130b. To achieve the desired phase shift, the two receiver antennas 130a, 130b need to be physically separated from each other. In practice, this means that the two receiver antennas 130a, 130b can be separated by a distance on the order of meters. Further, the split-mount transmitter arrangement 110a also comprises a multiple-output transmitter (not shown in Fig. 1) and the split-mount receiver arrangement 110b also comprises a multiple-input receiver (not shown in Fig. 1). In the illustrated example, the multiple-output transmitter is included in a hub 140a arranged near the bottom of the first mast and the multiple-input receiver is included in a hub 140b arranged near the bottom of the second mast. There is an analog connection (as schematically indicated by a dash-dot-dotted lines) between each of the two receiver antennas 130a, 130b and the multiple-input receiver. Fig. 2 is a block diagram of a multiple-input receiver 200 comprising a first receiver unit 210a (denoted Rx1) and a second receiver unit 210b (denoted Rx2). The two receiver units 210a, 210b are identical to each other. Each receiver unit 210a, 210b comprises analog processing circuitry 214a, 214b configured to process analog signals as received over the air by antennas 212a, 212b. The analog signals as received by each receiver unit 210a, 210b is provided over an analog signal interface 222a, 222b to the other receiver unit 210a, 210b. Both its own analog signals and the analog signals received from the other receiver unit 210a, 210b are then converted to digital form by respective analog-to-digital converters 216a, 216b, 218a, 218b. The resulting digital signals can then be processed by a digital processing unit 220a, 220b in each receiver unit 210a, 210b, producing a respective received data stream (denoted Rx data stream 1 and Rx data stream 2 in Fig. 2).

[0009] Accordingly, each receiver unit 210a, 210b needs both its own analog signals as well as the analog signals from the other receiver unit 210a, 210b. This extends for higher orders of Ml MO so more and more analog signals are needed. Further, a separate analog-to-digital converter 216a, 216b, 218a, 218b is required for each signal. Although the analog signal interface 222a, 222b are only schematically illustrated in Fig. 2, each analog signal interface 222a, 222b needs contacting, lightning protection, and cabling, which can make the signal interfaces 222a, 222b both bulky and expensive. Again, this extends for higher orders of MIMO so more and more analog signals are needed. Further, each galvanically connected signal interface is a potential cause of electromagnetic compatibility (EMC) issues and lightning problems. All in all, this makes the receiver units 210a, 210b bulky, expensive, and prone to problems. Hence, there is a need for improved receiver units for a microwave link site.

[0010] SUMMARY

[0011] An object of embodiments herein is to address the above issues with existing receiver units.

[0012] A particular object is to provide a receiver unit that is less bulky, less expensive, and less prone to problems than the aforementioned receiver units.

[0013] A particular object is to provide a receiver unit with an improved interface to other receiver units within the receiver of a microwave link site.

[0014] According to a first aspect there is presented a receiver unit for a microwave link site. The receiver unit comprises analog processing circuitry configured to process an analog signal as received over the air by an antenna of the microwave link site. The receiver unit comprises an analog-to-digital converter configured to convert the analog signal, as processed by the analog processing circuitry, to a first digital signal. The receiver unit comprises a digital signal interface configured to send the first digital signal to at least one further receiver unit of the microwave link site over a digital connection and to receive a respective second digital signal from each of said at least one further receiver unit over the digital connection. The receiver unit comprises a digital processing unit configured to process the first digital signal and said respective second digital signal. According to a second aspect there is presented a method for processing signals by a receiver unit of a microwave link site. The method is performed by the receiver unit, comprises processing, by an analog processing circuitry, an analog signal as received over the air by an antenna of the microwave link site. The method comprises converting, by an analog-to-digital converter, the analog signal, as processed by the analog processing circuitry, to a first digital signal. The method comprises sending, by a digital signal interface, the first digital signal to at least one further receiver unit of the microwave link site over a digital connection. The method comprises receiving, by the digital signal interface, a respective second digital signal from each of said at least one further receiver unit over the digital connection. The method comprises processing, by a digital processing unit, the first digital signal and said respective second digital signal.

[0015] According to a third aspect there is presented a computer program for processing signals by a receiver unit of a microwave link site. The computer program comprises computer code which, when run on processing circuitry of a receiver unit, causes the receiver unit to perform actions. One action comprises the receiver unit to process an analog signal as received over the air by an antenna of the microwave link site. One action comprises the receiver unit to convert the analog signal, as processed, to a first digital signal. One action comprises the receiver unit to send the first digital signal to at least one further receiver unit of the microwave link site over a digital connection. One action comprises the receiver unit to receive a respective second digital signal from each of said at least one further receiver unit over the digital connection. One action comprises the receiver unit to process the first digital signal and said respective second digital signal.

[0016] According to a fourth aspect there is presented a computer program product comprising a computer program according to the third aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium.

[0017] Advantageously, these aspects address the aforementioned issues with existing receiver units.

[0018] Advantageously, these aspects enable fiber optics to be used for signaling exchange between the receiver units, thereby eliminating the need for lightning protection on the interfaces. For example, In the case of a 4-by-4 MIMO microwave system where each receive unit implements a Cross Polar Interference Cancellation (XPIC) receiver, one single optical fiber cable will replace four coaxial cables. This can also reduce (or even eliminate) the amount of noise and / or signal distortion the signals exchanged between the receiver units are affected by.

[0019] Advantageously, by not having to duplicate the analog filtering and the analog-to-digital conversion, hardware can be saved.

[0020] Advantageously, as a side effect, the receiver units can exchange auxiliary information (such as frequency and time synchronization, configuration data, etc.) between each other using the digital connection.

[0021] Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, module, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic diagram illustrating a microwave system according to an example;

[0024] Fig. 2 is a block diagram of receiver units of a microwave link site according to an example;

[0025] Fig. 3 is a schematic diagram illustrating a microwave system according to an embodiment;

[0026] Fig. 4 is a block diagram of receiver units of a microwave link site according to an embodiment;

[0027] Figs. 5 and 6 are block diagrams of a receiver unit of a microwave link site according to embodiments;

[0028] Fig. 7 is a flowchart of methods according to embodiments;

[0029] Fig. 8 is a schematic diagram showing structural units of a receiver unit according to an embodiment; and

[0030] Fig. 9 shows one example of a computer program product comprising computer readable storage medium according to an embodiment.

[0031] DETAILED DESCRIPTION

[0032] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

[0033] As noted above, there is still a need for improved receiver units for a microwave link site.

[0034] The embodiments disclosed herein therefore relate to techniques for processing signals by a receiver unit of a microwave link site. In order to obtain such techniques, there is provided a receiver unit, a method performed by the receiver unit, a computer program product comprising code, for example in the form of a computer program, that when run on a receiver unit, causes the receiver unit to perform the method. Reference is here made to Fig. 3 in which is illustrated a non-limiting example of a line-of-sight 2-by-2 Ml MO microwave system 300 according to an embodiment. As in Fig. 1, the line-of-sight 2-by-2 MIMO microwave system 300 comprises a transmitter 310a and a receiver 310b, each connected to a respective hub 340a, 340b. In turn, the transmitter 310a comprises two transmitter units 320a, 320b, each associated with its own antenna, and the receiver 310b comprises two receiver units 330a, 330b, each associated with its own antenna. However, in contrast to Fig. 1, there is a digital connection (as schematically indicated by a dash-dotted line) between the two receiver units 330a, 330b. In this way, the exchange of analog signals as described with reference to Figs. 1 and 2 can be replaced with a digital representation of the signals. In this respect, since, as will be further disclosed below, digital signal processing is performed in each receiver unit 330a, 330b, the functionality of at least hub 340b can be simplified compared to the hub 140b in Fig. 1. In some examples, the hub 340b is configured to act as a router for the receiver units 330a, 330b and / or to provide power to the receiver units 330a, 330b. In some examples, the hub 340b is omitted. Further, in contrast to the situation described with reference to Figs. 1 and 2, the receiver units 330a, 330b are in this example placed physically close to their respective antennas. Placing the receiver units 330a, 330b in such a way may help to reduce signal losses and installation costs.

[0035] Fig. 4 is a block diagram of a receiver 400 comprising a N receiver units 410a, 410b, .... 410N (denoted Rx1, Rx2, .... RxN) according to an embodiment. The receiver units 410a:410N are identical to each other. Therefore, only the components of one of the receiver units, i.e., receiver unit 410a, are shown. Each receiver unit 410a:41 ON thus comprises analog processing circuitry 414 configured to process analog signals as received over the air by its antenna 412a, 412b, .... 412N. Further, each receiver unit 410a:41 ON comprises an analog-to-digital converter 415. The analog-to-digital converter 415 is configured to convert the analog signal, as processed by the analog processing circuitry 414, to a first digital signal. The analog-to-digital converter 415 may further be configured to perform digital filtering, symbol clock recovery, etc. Alternatively, the digital filtering can be performed separately, as will be further disclosed below. Further, each receiver unit 410a:41 ON comprises a digital signal interface 416. In some examples, the digital signal interface 416 is, is part of, or comprises, a Small Formfactor Pluggable (SFP) connector, or the like. The SFP connector could of different SFP types, such as a Quad SFP connector, an Octal SFP connector, or the like, and have a nominal speed from 100 Mbit / s up to 400 Gbit / s. In some examples, instead of having an SFP connector, or other dedicated, or separated, module that implements the functionality of the digital signal interface 416, the digital signal interface 416 is directly integrated with the receiver unit. For example, the digital signal interface 416 might comprise a module which is configured to be attached to a receiver unit 410a:410N and which module includes an optical transmitter, such as a laser or a photodiode, and drive electronics for the optical transmitter. The digital signal interface 416 is configured to send the first digital signal to at least one further receiver unit 410b:41 ON of the microwave link site over a digital connection 420a. The digital signal interface 416 is further configured to receive a respective second digital signal from each of the at least one further receiver unit 410b:410N over the digital connection 420a. The transfer rate of the digital connection is independent of the data rate of the signal processing in the receiver units (although it needs to be sufficiently high to transfer the data, e.g., in the order of 1 Gbit / s or higher). The data rate on the digital connection can thus be used to transfer frequency information between the receiver units. Accordingly, digital signals are thereby exchanged between the different receiver units 410a:41 ON. For illustrative purposes, the digital connection 420a is only illustrated as extending between receiver unit 410a and receiver unit 410b although receiver unit 410a has a digital connection to all receiver units 410b:41 ON, as is also the case for the remaining receiver units 410b:41 ON. However, in other examples, each receiver unit has only a connection to its adjacent receiver units. All connections are digital. All digital signals can then be multiplexed together and sent over this connection. This can be realized by means of multiplexer units such that a (first) multiplexer in receiver unit x, where a < x < N-1, multiplexes the digital signals received from receiver units a to x-1 and sends these digital signals towards receiver unit x+1 and a (second) multiplexer in receiver unit x multiplexes the digital signals received from receiver units x+1 to N and sends these digital signals towards receiver unit x-1, etc. The digital signals could here or in other examples be communicated according to a ring communication configuration, such as in accordance with a token ring topology. The digital connection 420a:420N could be, be part of, or comprise, an optical fiber connection. Further, each receiver unit 410a:410N comprises a digital processing unit 418 configured to process the first digital signal and each respective second digital signal, thus producing a respective received data stream (denoted Rx data stream 1, Rx data stream 2, .... Rx data stream N in Fig. 4). There can be different processing performed by the digital processing unit 418. For example, the digital processing unit 418 can be configured to apply multiple-input processing to the first digital signal and the second digital signals as part of processing the first digital signal and the second digital signals. An example where the processing as applied by the digital processing unit 418 comprises XPIC will be disclosed below with reference to Fig. 6.

[0036] Further aspects of the receiver units 410a:41 ON will be disclosed next with reference to Fig. 5. In Fig. 5 is provided a block diagram of one receiver unit 500 according to an embodiment. The receiver unit 500 can be implemented in the receiver units 330a, 330b, 410a:41 ON.

[0037] The receiver unit 500 comprises analog processing circuitry 502 configured to process analog signals as received over the air by an antenna of the receiver. There could be different types of processing performed by the analog processing circuitry 502. In some non-limiting examples, the processing comprises any, or any combination, of: filtering, frequency conversion, separation of in-phase (I) and quadrature (Q) components of the analog signals, etc. The receiver unit 500 comprises an analog-to-digital converter 504 configured to convert the analog signal, as processed by the analog processing circuitry 502, to a first digital signal. The first digital signal is subjected to filtering in a digital filter 524. In some non-limiting examples, the processing comprises any, or any combination, of: downsampling, filtering, clock recovery, resampling, carrier recovery, etc.

[0038] The thus filtered first digital signal is provided to an (optional) format unit 506. The format unit 506 is placed downstream the analog-to-digital converter 504 and upstream the digital signal interface 512 for transmission over a digital connection 522. The format unit 506 is configured to format the first digital signal into one format in a set of available formats. Different examples of formatting will be disclosed next. It is then the first digital signal as formatted that is sent to further receiver units of the receiver.

[0039] For example, if the communication over the digital connection 522 is packet based then the formatting might comprise packetizing the first digital signal into suitably sized packets. In some examples the format unit 506 comprises a packetize unit 508 configured to packetize the first digital signal into packets as part of formatting the first digital signal. However, in other examples, the first digital signal is streamed over the digital connection 522 without there being any need for packetization.

[0040] In some aspects, the first digital signal is combined with auxiliary information before being sent over the digital connection 522. Therefore, in some examples, the format unit 506 comprises a multiplex unit 510 configured to multiplex the first digital signal with auxiliary information as part of formatting the first digital signal. In some nonlimiting examples, the auxiliary information pertains to any, or any combination, of: frequency and time synchronization, configuration data, etc. such as timing information, frequency information, phase information, channel information, information to and / or from the digital processing unit 418, 520, network management information^. g., holding security information), etc. In case there are several antennas 412 in each receiver unit, then the multiplex unit 510 might be configured to multiplex the corresponding digital signals with each other before being sent over the digital connection 522. Further details of this will be disclosed below with reference to Fig. 6.

[0041] As above, the digital signal interface 512 is further configured to receive second digital signals from the other receiver units. Aspects of how these second digital signals can be processed in the receiver unit 500 will be disclosed next. In case the second digital signals have been formatted, then corresponding de-formatting needs to be applied. Therefore, the receiver unit 500 further comprises an (optional) a de-format unit 514. The de-format unit 514 is placed upstream the digital signal interface 512 and downstream the digital processing unit 520. In general terms, the de-format unit 514 is configured to perform the opposite operations of the format unit 506. Particularly, the de-format unit 514 is configured to remove formatting from each of the second digital signals. It is then the second digital signals with removed formatting that are processed by the digital processing unit 520.

[0042] In case the first digital signal has been multiplexed with auxiliary information, then the second digital signals are demultiplexed so that auxiliary information can be extracted from the second digital signals. Hence, in some examples, the de-format unit 514 comprises a de-multiplex unit 516 configured to extract auxiliary information as multiplexed with the second digital signals as part of removing formatting from the second digital signals.

[0043] Likewise, in case the first digital signal has been packetized, then the second digital signals are de-packetized. Hence, in some examples, the de-format unit 514 comprises a de-packetize unit 518 configured to de-packetize the second digital signals as part of removing formatting from the second digital signals.

[0044] Aspects where the analog signal received by the antenna 412a:412N comprises signals of two polarizations will be disclosed next with reference to Fig. 6.

[0045] In Fig. 6 is provided a block diagram of one receiver unit 600 according to an embodiment. The receiver unit 600 can be implemented in the receiver units 330a, 330b, 410a:41 ON, 500. The block diagram focuses on processing of signals with two polarizations and therefore many of the components of the receiver units 410a, 500 as illustrated in Figs. 4 and 5 have been excluded from the block diagram in Fig. 6. In general terms, the receiver unit 600 comprises respective analog processing circuitry 602a, 602b, analog-to-digital converts, digital filters, packetizing units 604a, 604b, de-packetize units 608a, 608b, and digital processing units 614a, 614b for each polarization. The functionality of these components has already been disclosed and apply here as well. However, it is noted that there is need for only one multiplex unit 606 and one de-multiplex unit 610. Further, for illustrative purposes, the digital signal interface has been illustrated to comprise one input part 612a (for receiving a second digital signal denoted “S2”) and one output part 612b (for sending a first digital signal denoted "S1”). An analog signal “ln_P1” with polarization P1 is received at analog processing circuitry 602a, and an analog signal “I n_P2” with polarization P2 is received at analog processing circuitry 602b. In some examples, P2 is orthogonal to P1. Further, auxiliary information sent to other receiver unts is denoted "auxiliary information out” whereas auxiliary information received from other receiver unts is denoted "auxiliary information in”. The block diagram in Fig. 6 is an example where the analog processing circuitry 602a, 602b, the analog-to-digital converters, and the digital signal interface 612a, 612b are configured to process signals corresponding to the two polarizations P1 and P2 separately, and the digital processing units 614a, 614b are configured to process the signals corresponding to the two polarizations jointly. In this way, the receiver unit 600 can perform XPIC with respect to the signals “ln_P1” and "ln_P2”.

[0046] Referring back to Fig. 3, the microwave link site 300 might comprise at least two receiver units 330a, 330b, 410a:41 ON, 500, 600 as herein disclosed. The digital signal interface 416, 512 of each of the at least two receiver units 330a, 330b, 410a:41 ON, 500, 600, 800 is configured to send a respective digital signal to each further receiver unit 330a, 330b, 410a:41 ON, 500, 600 of the microwave link site 300 over the digital connection 420a:420N, 522 and to receive a respective further digital signal from said each further receiver unit 330a, 330b, 410a:410N, 500, 600 over the digital connection 420a:420N, 522.

[0047] Fig. 7 is a flowchart illustrating embodiments of methods for processing signals by a receiver unit 330a, 330b, 410a:41 ON, 500, 600 of a microwave link site 300. The methods are performed by the receiver unit 330a, 330b, 410a:410N, 500, 600 according to any of the aforementioned embodiments, aspects, and examples. The methods are advantageously provided as computer programs.

[0048] S102: The analog processing circuitry 414, 502 processes an analog signal as received over the air by an antenna 412a:412N of the microwave link site 300.

[0049] S104: The analog-to-digital converter 415, 504 converts the analog signal, as processed by the analog processing circuitry 414, 502, to a first digital signal.

[0050] S108: The digital signal interface 416, 512 sends the first digital signal to at least one further receiver unit 330a, 330b, 410a:41 ON, 500, 600 of the microwave link site 300 over a digital connection 420a:420N, 522.

[0051] S110: The digital signal interface 416, 512 receives a respective second digital signal from each at least one further receiver unit 330a, 330b, 410a:41 ON, 500, 600 over the digital connection 420a:420N, 522.

[0052] S114: The digital processing unit 418, 520 processes the first digital signal and each respective second digital signal. Embodiments relating to further details of processing signals by a receiver unit 330a, 330b, 410a:41 ON, 500, 600 of a microwave link site 300 as performed by the receiver unit 330a, 330b, 410a:41 ON, 500, 600 will now be disclosed with continued reference to Fig. 7.

[0053] As disclosed above, the first digital signal may be formatted before being sent over the digital connection 420a:420N, 522. Therefore, in some embodiments, the method comprises (optional) step S106.

[0054] S106: The format unit 506 formats the first digital signal into one format in a set of available formats. It is then the first digital signal as formatted that is sent to the at least one further receiver unit 330a, 330b, 410a:41 ON, 500, 600. Examples of different formatting operations have been disclosed above and apply here as well.

[0055] As disclosed above, each second digital signal may be de-formatted before being processed by the digital processing unit 418, 520. Therefore, in some embodiments, the method comprises (optional) step S112.

[0056] S112: The de-format unit 514 removes formatting from each of the respective second digital signals. It is then each of the respective second digital signals with removed formatting that is processed by the digital processing unit 418, 520. Examples of different de-formatting operations have been disclosed above and apply here as well.

[0057] Fig. 8 schematically illustrates, in terms of a number of structural units, the components of a receiver unit 800 according to an embodiment. Processing circuitry 810 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 910 (as in Fig. 9), e.g. in the form of a storage medium 830. The processing circuitry 810 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

[0058] Particularly, the processing circuitry 810 is configured to cause the receiver unit 800 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 830 may store the set of operations, and the processing circuitry 810 may be configured to retrieve the set of operations from the storage medium 830 to cause the receiver unit 800 to perform the set of operations. The set of operations may be provided as a set of executable instructions.

[0059] Thus, the processing circuitry 810 is thereby arranged to execute methods as herein disclosed. The storage medium 830 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. The receiver unit 800 may further comprise a communications (comm.) interface 820 at least configured for communications with other entities, functions, nodes, and devices, such as other receiver units, transmitter units, and hubs, as in Figs. 3, 4, 5, and 6. As such the communications interface 820 may comprise one or more transmitters and receivers, comprising analogue and digital components. The processing circuitry 810 controls the general operation of the receiver unit 800 e.g. by sending data and control signals to the communications interface 820 and the storage medium 830, by receiving data and reports from the communications interface 820, and by retrieving data and instructions from the storage medium 830. Other components, as well as the related functionality, of the receiver unit 800 are omitted in order not to obscure the concepts presented herein.

[0060] Fig. 9 shows one example of a computer program product 910 comprising computer readable storage medium 930. On this computer readable storage medium 930, a computer program 920 can be stored, which computer program 920 can cause the processing circuitry 810 and thereto operatively coupled entities and devices, such as the communications interface 820 and the storage medium 830, to execute methods according to embodiments described herein. The computer program 920 and / or computer program product 910 may thus provide means for performing any steps as herein disclosed.

[0061] In the example of Fig. 9, the computer program product 910 is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 910 could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 920 is here schematically shown as a track on the depicted optical disk, the computer program 920 can be stored in any way which is suitable for the computer program product 910.

[0062] The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.

Claims

CLAIMS1. A receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) for a microwave link site (300), wherein the receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) comprises:analog processing circuitry (414, 502) configured to process an analog signal as received over the air by an antenna (412a:412N) of the microwave link site (300);an analog-to-digital converter (415, 504) configured to convert the analog signal, as processed by the analog processing circuitry (414, 502), to a first digital signal;a digital signal interface (416, 512) configured to send the first digital signal to at least one further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) of the microwave link site (300) over a digital connection (420a:420N, 522) and to receive a respective second digital signal from each of said at least one further receiver unit (330a, 330b, 410a:410N, 500, 600, 800) over the digital connection (420a:420N, 522); anda digital processing unit (418, 520) configured to process the first digital signal and said respective second digital signal.

2. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to claim 1, wherein the receiver unit (330a, 330b, 410a:410N, 500, 600, 800) further comprises:a format unit (506), placed downstream the analog-to-digital converter (415, 504) and upstream the digital signal interface (416, 512), and configured to format the first digital signal into one format in a set of available formats, and wherein it is the first digital signal as formatted that is sent to said at least one further receiver unit (330a, 330b, 410a:410N, 500, 600, 800).

3. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to claim 2, wherein the format unit (506) comprises a packetize unit (508) configured to packetize the first digital signal into packets as part of formatting the first digital signal.

4. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to claim 2 or 3, wherein the format unit (506) comprises a multiplex unit (510) configured to multiplex the first digital signal with auxiliary information as part of formatting the first digital signal.

5. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to any preceding claim, wherein the receiver unit (330a, 330b, 410a:410N, 500, 600, 800) further comprises:a de-format unit (514), placed upstream the digital signal interface (416, 512) and downstream the digital processing unit (418, 520), and configured to remove formatting from each of said respective second digital signal, and wherein it is each of said respective second digital signal with removed formatting that is processed by the digital processing unit (418, 520).

6. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to claim 5, wherein the de-format unit (514) comprises a de-multiplex unit (516) configured to extract auxiliary information as multiplexed with said respective second digital signal as part of removing formatting from each of said respective second digital signal.

7. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to claim 4 or 6, wherein the auxiliary information pertains to any, or any combination, of: timing information, frequency information, phase information, channel information, information to and / or from the digital processing unit (418, 520), network management information.

8. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to claim 5 or 6, wherein the de-format unit (514) comprises a de-packetize unit (518) configured to de-packetize each of said respective second digital signal as part of removing formatting from each of said respective second digital signal.

9. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to any preceding claim, wherein the digital signal interface (416, 512) is, is part of, or comprises, a Small Formfactor Pluggable, SFP, connector.

10. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to any preceding claim, wherein the digital connection (420a:420N, 522) is, is part of, or comprises, an optical fiber connection.

11. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to any preceding claim, wherein the digital processing unit (418, 520) is configured to apply multiple-input processing to the first digital signal and said respective second digital signal as part of processing the first digital signal and said respective second digital signal.

12. The receiver unit (330a, 330b, 410a:410N, 500, 600, 800) according to any preceding claim, wherein the analog signal received by the antenna (412a:412N) comprises signals of two polarizations, and wherein the analog processing circuitry (414, 502), the analog-to-digital converter (415, 504), and the digital signal interface (416, 512) are configured to process the signals corresponding to the two polarizations separately, and the digital processing unit (418, 520) is configured to process the signals corresponding to the two polarizations jointly.

13. A microwave link site (300), the microwave link site (300) comprising at least two receiver units (330a, 330b, 410a:410N, 500, 600, 800) according to any preceding claim, wherein the digital signal interface (416, 512) of each of the at least two receiver units (330a, 330b, 410a:41 ON, 500, 600, 800) is configured to send a respective digital signal to each further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) of the microwave link site (300) over the digital connection (420a:420N, 522) and to receive a respective further digital signal from said each further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) over the digital connection (420a:420N, 522).

14. A method for processing signals by a receiver unit (330a, 330b, 410a:410N, 500, 600, 800) of a microwave link site (300), wherein the method is performed by the receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) and comprises:processing (S102), by an analog processing circuitry (414, 502), an analog signal as received over the air by an antenna (412a:412N) of the microwave link site (300);converting (S104), by an analog-to-digital converter (415, 504), the analog signal, as processed by the analog processing circuitry (414, 502), to a first digital signal;sending (S108), by a digital signal interface (416, 512), the first digital signal to at least one further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) of the microwave link site (300) over a digital connection (420a:420N, 522);receiving (S110), by the digital signal interface (416, 512), a respective second digital signal from each of said at least one further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) over the digital connection (420a:420N, 522); andprocessing (S114), by a digital processing unit (418, 520), the first digital signal and said respective second digital signal.

15. The method according to claim 14, wherein the method further comprises:formatting (S106), by a format unit (506) placed downstream the analog-to-digital converter (415, 504) and upstream the digital signal interface (416, 512), the first digital signal into one format in a set of available formats, and wherein it is the first digital signal as formatted that is sent to said at least one further receiver unit (330a, 330b, 410a:410N, 500, 600, 800).

16. The method according to claim 14 or 15, wherein the method further comprises:removing (S112), by a de-format unit (514) placed upstream the digital signal interface (416, 512) and downstream the digital processing unit (418, 520), formatting from each of said respective second digital signal, and wherein it is each of said respective second digital signal with removed formatting that is processed by the digital processing unit (418, 520).

17. A computer program (920) for processing signals by a receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) of a microwave link site (300), the computer program comprising computer code which, when run on processing circuitry (810) of the receiver unit (330a, 330b, 410a:410N, 500, 600, 800), causes the receiver unit (330a, 330b, 410a:410N, 500, 600, 800) to:process (S102) an analog signal as received over the air by an antenna (412a:412N) of the microwave link site (300);convert (S104) the analog signal, as processed, to a first digital signal;send (S108) the first digital signal to at least one further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) of the microwave link site (300) over a digital connection (420a:420N, 522);receive (S110) a respective second digital signal from each of said at least one further receiver unit (330a, 330b, 410a:41 ON, 500, 600, 800) over the digital connection (420a:420N, 522); andprocess (S114) the first digital signal and said respective second digital signal.

18. A computer program product (910) comprising a computer program (920) according to claim 17, and a computer readable storage medium (930) on which the computer program is stored.

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