Transceiver with a beamforming device

Abstract

A transceiver is provided that comprises a beamforming device, at least one transmitter and at least one receiver. The beamforming device comprises a lens or passive beamforming network having a plurality of first ports and a plurality of second ports, and an antenna array comprising a plurality of antennas. Each of a plurality of the second ports is connected to a respective antenna of the plurality of antennas, and each first port corresponds to a respective beam direction of a signal transmitted from and / or received at the antenna array. The at least one transmitter has an output connected or connectable to a first one or more of the plurality of first ports, and the at least one receiver has an input connected or connectable to a second one or more of the plurality of first ports. The at least one transmitter and the at least one receiver are configured to simultaneously transmit at least one signal from the plurality of antennas and receive at least one signal from the plurality of antennas.

Description

[0001] TRANSCEIVER WITH A BEAMFORMING DEVICE

[0002] Technical Field

[0003] Examples of this disclosure relate to a transceiver, for example in a wireless communications device.

[0004] Background

[0005] Full-Duplex (FD) wireless communication - simultaneous transmission and reception on the same frequency at the same time - has the potential to double throughput and reduce latency, and is thereby subject to considerable interest. The fundamental challenge is that the strong transmitter signal leaks into the receiver, causing so-called self-interference (SI). To be able to successfully receive the intended signal, which can be very weak, the self-interference must be very well suppressed by isolation and cancellation schemes. To obtain a high degree of isolation and cancellation, isolation and cancellation techniques in multiple signal domains can be combined. For example, isolation in the radio frequency (RF) domain can be combined with analog baseband (BB) or intermediate frequency (IF) techniques, and / or digital baseband techniques.

[0006] Another important technology is beamforming, which can enhance a communication link’s range, signal-to-noise ratio (SNR), and spatial selectivity. It can be applied to both transmitter (Tx) and receiver (Rx), and uses multiple antenna elements in an array. The signals provided to the antenna elements have different phases or different time delays. The direction of the beam is controlled by the differences in phase or time between antenna element signals.

[0007] Isolation at RF is always needed in FD transceivers, and it can be achieved with active or passive circulators, electrical balance duplexers (EBD), or separated Tx and Rx antennas. The passive circulator is a bulky and expensive external component between the transceiver integrated circuit (IC) and antenna. Active circulators are integrated solutions, but suffer from limited power handling capability and noise figure (NF) performance. An EBD can provide high isolation and power handling capabilities but has a minimum theoretical 3 dB insertion loss both for Tx and Rx and requires tuning. These shortcomings limit the FD performance compared to half-duplex (HD) communication in terms of power handling capability, noise figure, and wideband isolation, leading to data rates lower than 2x of that of HD communication. To combine FD and beamforming, the FD multi-antenna system can be implemented using separate antenna arrays for the transmitter and receiver, thus exploiting the separation between Tx and Rx antennas to provide some isolation. Another alternative, in case there is insufficient space for separate Rx and Tx arrays, is to use a shared antenna array having a circulator between each antenna element and the corresponding Tx and Rx channels. However, both these alternatives require SI cancellation for each pair of Tx and Rx antenna elements, either in the same shared antenna array or cross-leakage between the Tx and Rx antenna arrays. This requires an M x N number of SI cancellers in the analog domain, where M is the number of Tx array elements and N is number of Rx array elements. This will provide a very high complexity, effectively preventing FD from being combined with large antenna array sizes.

[0008] Summary

[0009] Some examples of this disclosure may mitigate one or more of the above-identified problems. For example, examples of this disclosure may combine FD and beamforming without requiring an array of cancellation units. Examples of this disclosure may provide high RF isolation between Tx and Rx ports to which transmitters and receivers are connected, with low loss. Some examples may allow for elimination of Rx and Tx switches, which is suitable for very high frequencies.

[0010] One aspect of the present disclosure provides a transceiver comprising a beamforming device, at least one transmitter and at least one receiver. The beamforming device comprises a lens or passive beamforming network having a plurality of first ports and a plurality of second ports, and an antenna array comprising a plurality of antennas. Each of a plurality of the second ports is connected to a respective antenna of the plurality of antennas, and each first port corresponds to a respective beam direction of a signal transmitted from and / or received at the antenna array. The at least one transmitter has an output connected or connectable to a first one or more of the plurality of first ports, and the at least one receiver has an input connected or connectable to a second one or more of the plurality of first ports. The at least one transmitter and the at least one receiver are configured to simultaneously transmit at least one signal from the plurality of antennas and receive at least one signal from the plurality of antennas.

[0011] Another aspect of the present disclosure provides a wireless communications device comprising the transceiver of the above aspect. Brief Description of the Drawings

[0012] For a better understanding of the embodiments of the present disclosure, and to show how it may be put into effect, reference will now be made, by way of example only, to the accompanying figures, in which:

[0013] Figure 1 illustrates an example of a transceiver according to embodiments of this disclosure;

[0014] Figure 2 illustrates an example of a beamforming device according to embodiments of this disclosure;

[0015] Figure 3 illustrates another example of a transceiver according to embodiments of this disclosure;

[0016] Figure 4 illustrates another example of a transceiver according to embodiments of this disclosure;

[0017] Figure 5 illustrates another example of a transceiver according to embodiments of this disclosure;

[0018] Figure 6 shows an example of a graph of insertion loss against frequency for an example Rotman lens design; and

[0019] Figure 7 shows an example of a graph of normalized array factor for a beamforming device according to this disclosure.

[0020] Detailed Description

[0021] The following sets forth specific details, such as particular embodiments or examples for purposes of explanation and not limitation. It will be appreciated by one skilled in the art that other examples may be employed apart from these specific details. In some instances, detailed descriptions of well-known methods, nodes, interfaces, circuits, and devices are omitted so as not obscure the description with unnecessary detail. Those skilled in the art will appreciate that the functions described may be implemented in one or more nodes using hardware circuitry (e.g. analog and / or discrete logic gates interconnected to perform a specialized function, Application Specific Integrated Circuits (ASICs), Programmable Logic Arrays (PLAs), etc.) and / or using software programs and data in conjunction with one or more digital microprocessors or general purpose computers. Nodes that communicate using the air interface also have suitable radio communications circuitry. Moreover, where appropriate parts of the technology can additionally be considered to be embodied entirely within any form of computer-readable memory, such as solid-state memory, magnetic disk, or optical disk containing an appropriate set of computer instructions that would cause a processor to carry out the techniques described herein. Example embodiments of this disclosure propose a full duplex (FD) beamforming transceiver solution, in which at least one transmitter and at least one receiver are configured to simultaneously transmit at least one signal from a plurality of antennas and receive at least one signal from the plurality of antennas. Example embodiments may operate at millimeter wave (mmWave) frequencies. In some examples, a beamforming device comprising a lens (e.g. a Rotman lens) or a passive beamforming network is provided between the antennas and the integrated circuit(s) comprising the transmitter(s) and receiver(s).

[0022] The beamforming device may be connected to a one-dimensional antenna array. The beamforming device performs passive beamforming for example for a single transceiver connected to a pair of the beamforming device’s beam ports. The beamforming device can (dependent on substrate material properties and frequency of operation in some examples) have a low insertion loss, and according to simulations can provide about 20 dB of isolation over a wide bandwidth between two adjacent ports on the transceiver side. Using the overlapping beams of two adjacent ports, this can in some examples enable simultaneous transmit and receive in substantially the same direction with as low as 1-2 dB loss for either the transmission or reception using two adjacent ports. The loss in TX / RX may in some examples depend on the position of a device containing the transceiver, and the overlapping beam crossover level of the adjacent ports.

[0023] In some examples, beam ports of the beamforming device are connected to the transmitter(s) and receiver(s). For example, each port may be connected through switches or multiplexers to one or a few transmitters / receivers, or directly to multiple transmitter(s) and / or receiver(s).

[0024] Examples of this disclosure propose two modes of FD beamforming operations using a single transmitter and receiver, or transceiver. The first mode is to simultaneously transmit and receive in substantially the same direction, called symmetric FD. The second mode of FD operation, simultaneously transmit and receive in different directions, is called asymmetric FD. In both modes of operation, the beamforming device may have low insertion loss between the transmitter and the antennas, and between the antennas and the receiver. According to simulation, some examples may have about 20 dB of isolation between adjacent ports (referred to herein as first ports, and also in some examples as beam ports) and also between other first ports. In addition, spatial filtering, as provided by the beamforming device in some examples, may help to reduce the magnitude of multipath components in the radio channel, thus relaxing the number of taps requirements in an analog SI rejection filter, if present, in RF or other signal domains. Where switches are used, in an example, even numbered beam ports can be connected to receivers or receiver switches / multiplexers, whereas odd numbered beam ports can be connected to transmitters or transmitter switches / multiplexers. The multiplexer can then in such examples connect any of the even numbered ports to a receiver and any of the odd numbered ports to a transmitter. It may then be possible to simultaneously use one adjacent beam for reception and one for transmission for any beam pair, but not to select which one is used for which. This reduces the size of the multiplexer / switches to by half, reducing complexity and losses. Where switches are not used, every other beam port (e.g. even numbered ports) can each be connected to a respective receiver in some examples and every other beam port (e.g. odd numbered ports) to a transmitter, but instead of using switches, each receiver and transmitter is activated or inactivated in order to choose which beam ports are used. This may be beneficial for example at high frequencies, such as above about 100GHz, where switch losses are prohibitive.

[0025] If restricted to operating in symmetric FD, the beam selection switches can be simplified. Every even order beam port can then be assigned to Rx and every odd port to Tx, as suggested above for example, or vice versa. In this disclosure, in some examples, the port numbering is arbitrary, though an odd numbered port is generally located adjacent to an even numbered port.

[0026] Figure 1 illustrates an example of a transceiver 100 according to embodiments of this disclosure. The transceiver 100 includes a beamforming device 102. The beamforming device 102 comprises a lens or passive beamforming network 104 having a plurality of first ports 106 and a plurality of second ports 108. In this example, there are four first ports 106 and four second ports 108, although in other examples there may be any number of first ports and second ports, and there may be a different number of first ports and second ports.

[0027] The beamforming device 102 also includes an antenna array 110 comprising a plurality of antennas 112. Each of a plurality of the second ports 108 is connected to a respective antenna 112 of the plurality of antennas, and thus in the example shown there are four antennas 112, each connected to a different second port 108. Furthermore, each first port 106 corresponds to a respective beam direction of a signal transmitted from and / or received at the antenna array.

[0028] That is, for example, the lens or passive beamforming network 104 may be configured such that, for each first port 106, a signal provided to the first port 106 propagates to each second port 108 with a respective phase of the first signal. In other words, for example, a signal provided to a first one of the first ports 106 arrives at each second port 108 with a respective phase, which may be different between the second ports, and hence forms a beam when transmitted from antennas 112. On the other hand, for example, a signal provided to a second one of the first ports 106 arrives at each second port 108 with a respective phase, which may be different between the second ports and also may be different to the phase of the signal if it was provided to the first one of the first ports 106. Hence forms a beam when transmitted from antennas 112, and the beam direction may be different to the beam direction if the first one of the first ports is used. Therefore, in some examples, the lens or passive beamforming network is configured such that, for each first port, the respective phase of the signal at each second port from the first port causes the signal to be transmitted in the respective beam direction for the first port, and thus the selection of the first port 106 to which the signal is provided (e.g. to which a transmitter is connected) selects the beam direction of the transmitted signal. Similarly, in some examples, the selection of the first port 106 at which a signal is received (e.g. to which a receiver is connected) selects the beam direction of a received signal.

[0029] The transceiver 100 further comprises at least one transmitter 114 having an output connected or connectable to a first one or more of the plurality of first ports 106, and at least one receiver 116 having an input connected or connectable to a second one or more of the plurality of first ports 106. In the example shown in Figure 1, one transmitter 114 and one receiver 116 are shown, though in other examples there may be any number of transmitters and receivers, and there may also be a different number of transmitters and receivers. In Figure 1 , the transmitter 114 and receiver 116 are shown not connected to the first ports 106. This is because there are various ways to connect the transmitter 114 and receiver 116 to the first ports 106, and this connection may be fixed or configurable depending on the implementation. Further details are provided below.

[0030] The at least one transmitter 114 and the at least one receiver 116 are configured to simultaneously transmit at least one signal from the plurality of antennas 112 and receive at least one signal from the plurality of antennas 112, thus achieving full duplex communication. The lens or passive beamforming network may be configured for example such that, for each of the plurality of the second ports, a phase of a signal at the second port from a selected one of the first ports is dependent on the selected first port.

[0031] In some examples, beams corresponding to adjacent first ports 106 at least partially overlap. As a result, in some examples, symmetric FD may be achieved. For example, adjacent first ports can be used for simultaneous transmission and reception with a single device, or multiple devices that are located substantially in the same direction. In some examples, the lens or passive beamforming network comprises a Rotman lens or a Butler matrix. Figure 2 illustrates an example of a beamforming device 200 which could be used as the beamforming device 102 shown in Figure 1. The beamforming device 200 includes a Rotman lens 202 connected to first ports 204 and second ports 206. The second ports are each connected to a respective antenna 208 (some antennas are omitted from Figure 2 for clarity). The first ports 204 may be connected to one or more transmitters and one or more receivers, for example directly or via multiplexers or switches in the manner described herein.

[0032] In some examples, the transceiver 100 includes a multiplexer (not shown) that is configured to connect the output of each of the at least one transmitter 114 to any selected first port 106 of the plurality of first ports, and to connect the input of each of the at least one receiver 116 to any selected first port 106 of the plurality of first ports. As a result, for example, any of the beam directions can be used by any of the transmitter(s), and any of the beam directions can be used by any of the receiver(s).

[0033] Figure 3 illustrates an example of a transceiver 300 that includes the beamforming device 200 shown in Figure 2, and which includes the above arrangement. The transceiver includes a multiplexer 302 connected between the beamforming device 200 and both a transmitter 304 and a receiver 306. The multiplexer 302 is configured such that the output of the transmitter 304 (e.g. an output of a power amplifier, PA, 308 in the transmitter 304) can be selectively connected to any one of the first ports 204, and the input of the receiver 306 (e.g. an input of a low noise amplifier, LNA, 310 in the receiver 306) can also be selectively connected to any one of the first ports 204. In the example transceiver 300 shown in Figure 3, the transceiver 300 also includes self-interference cancellation (SIC) apparatus 312 that comprises a coupler 314, phase and amplitude adjuster 316 (which may also be referred to in some examples as a variable phase shifter and attenuator), and summer 318 to extract a portion of the signal output from PA 308, adjust its phase and / or amplitude and provide the resulting signal to the summer 318 to add it to the input of LNA 310 and hence cancel at least some of the self-interference from the transmitter 304 in the receiver 306.

[0034] In other examples, however, the transceiver 100 includes a multiplexer (not shown) that is configured to connect the output of each of the at least one transmitter 114 to any selected first port of a first subset of the first ports 106, and connect the input of each of the at least one receiver 116 to any selected first port of a second subset of the first ports 106, wherein the first subset is different to the second subset. In such cases, the multiplexer may be smaller and / or fewer switches may be used compared to the case illustrated above where any of the beam directions can be used by any of the transmitter(s) and receiver(s). In some examples, the first subset and the second subset include no common first port, i.e. there is no overlap between the first and second subsets, although there may be some overlap in some examples.

[0035] In particular examples, each first port in the first subset is adjacent to a first port in the second subset, and / or each first port in the second subset is adjacent to a first port in the first subset. For example, as suggested above, the first subset may include odd numbered ports of the first ports 106 and the second subset may comprise even numbered ports of the first ports 106.

[0036] Figure 4 illustrates an example of a transceiver 400 that includes such an arrangement, and includes the beamforming device 200 shown in Figure 2. Features and components similar to those in Figure 3 are given the same reference numerals. In contrast to the transceiver 300 Figure 3, the transceiver 400 of Figure 4 includes a multiplexer 402 that selectively connects the transmitter 304 to a selected one of a first subset of the first ports, indicated by solid lines 404. Similarly, the multiplexer 402 selectively connects the receiver 306 to a selected one of a second subset of the first ports 406. The first and second subsets are arranged in an alternating pattern, such that each port of the first subset is adjacent to at least one port of the second subset, and vice versa. For example, the first subset 404 of ports may be even numbered ports of the beamforming device 200, and the second subset 406 of ports may be odd numbered ports of the beamforming device 200, or vice versa.

[0037] In some examples, the at least one transmitter 114 comprises a plurality of transmitters having outputs connected or connectable to different first ports of the plurality of first ports. For example, there may be the same number of transmitters 114 as first ports 106, each transmitter connected to a different first port 106. Alternately, in some examples there may be fewer transmitters than first ports 106, and the transmitters may each be directly connected to a particular first port 106 or may be connected or connectable via a multiplexer or switches to any of the first ports 106 or the first subset of first ports 106 as suggested above.

[0038] Similarly, in some examples, the at least one receiver 116 comprises a plurality of receivers having outputs connected or connectable to different first ports of the plurality of first ports. For example, there may be the same number of receivers 116 as first ports 106, each receiver connected to a different first port 106. Alternately, in some examples there may be fewer receivers than first ports 106, and the receivers may each be directly connected to a particular first port 106 or may be connected or connectable via a multiplexer or switches to any of the first ports 106 or the first subset of first ports 106 as suggested above. In some examples, there may be the same number of total transmitters and receivers as first ports, where each transmitter and receiver is connected to a different port. Figure 5 illustrates an example of a transceiver 500 that includes the same total number of transmitters and receivers as first ports, i.e. in this example there are nine first ports 204, five transmitters 304 and four receivers 306. The transmitters 304 and receivers 306 are in this example connected directly to their respective first port 204 in an alternating manner, so for example the transmitters 304 are connected to odd numbered ports and the receivers 306 are connected to even numbered ports of the beamforming device 200. Thus, for example, different transmit or receive beam directions can be selected by using different transmitters and / or receivers, or multiple beam directions can be used simultaneously by utilizing multiple transmitters and / or receivers.

[0039] In the example transceiver 500 shown in Figure 5, the transceiver 500 also includes selfinterference cancellation (SIC) apparatus 502 that comprises couplers 504 (each coupler 504 coupled to an output of a respective PA 308), phase and amplitude adjuster 506 (which may also be referred to in some examples as a variable phase shifter and attenuator), and summers 508. The SIC apparatus 502 also includes a first multiplexer 510 and a second multiplexer 512. The first multiplexer 510 is arranged to connect a selected one of the couplers 504 to the phase and amplitude adjuster 506, and the second multiplexer 512 is arranged to connect the output of the phase and amplitude adjuster 506 to a selected one of the summers 508.

[0040] Each summer 508 is arranged to receive a signal from second multiplexer 512 (when selected) and add it to the input of a respective LNA 310. Thus, the SIC apparatus can be used in some examples to extract a portion of a signal from a selected one of the PAs 308 and provide an adjusted signal to the input of a selected one of the LNAs 310, and hence cancel at least some of the self-interference from a selected transmitter 304 in a selected receiver 306. This may be useful for example when only a single transmitter 304 is used at a time, and only a single receiver 306 is used at a time.

[0041] In some examples, as suggested above, the transceiver according to examples of this disclosure is configured for asymmetric FD. Therefore, for example, the transmitter may be configured to transmit a first signal on a first beam using a first port corresponding to a beam direction in a direction of a first wireless communications device, and the receiver may be configured to receive a second signal on a second beam using a first port corresponding to a beam direction in a direction of a second wireless communications device. The first beam may at least partially overlap with the second beam, or does not overlap with the second beam. Alternatively, in some examples, as suggested above, the transceiver according to examples of this disclosure is configured for symmetric FD. Therefore, for example, the transmitter may be configured to transmit a first signal using a first port corresponding to a beam direction in a direction of a first wireless communications device, and the receiver may be configured to receive a second signal using a first port corresponding to a beam direction in a direction of the first wireless communications device, wherein the first beam at least partially overlaps with the second beam. In some examples, the transmitter is configured to transmit the first signal using one of the first ports and the receiver is configured to receive the second signal using a different one of the first ports.

[0042] To illustrate the performance of examples of this disclosure, a planar Rotman lens was used in simulations. The HFSS 3D-EM tool was used for simulating the lens. The simulations were done in a 50-ohm environment. That is, the impedance of all signal generators and loads connected to the ports of the lens is 50 Ohms. The lens was designed with a 30 GHz center frequency, with 9 beam ports (first ports) and 8 antenna ports (second ports), and around 80x80 mm2active area. If designed at other center frequencies, the area may be inversely proportional to the square of the frequency, so for instance at 60GHz center frequency the area would be around 40x40 mm2. The designed lens, which can be implemented in some examples in metal on a printed circuit board (PCB), has a maximum ±30-degree steering angle, and the main beam step size (the difference between two adjacent beam directions) depends on the maximum steering angle and number of beam ports. The beam step size in this example design is about 6.6 degrees, the 3-dB beamwidth is 12.5 degrees, and the maximum beam cross-over level is about 1 dB between the adjacent beam ports, in the scenario where the UE is in the middle of the two beams, a Tx beam and an Rx beam, from / to the beam ports. The resulting wideband isolation between adjacent ports is below about -17 dB from 28-30 GHz.

[0043] The power loss in the lens is estimated by feeding a 0 dBm signal to port 5 (the center first port) and adding up the power delivered to all the antenna ports, and comparing it to the power fed to the input port. The loss in the lens is shown in Figure 6, which shows an example of a graph of insertion loss against frequency for the example Rotman lens design. The insertion loss is calculated as the ratio of the sum of the complex power at each antenna port to power fed to the input port. The resulting total insertion loss in the Rotman lens is from -2.5 to -4 dB when input is fed to port 5, shown in Figure 6.

[0044] Figure 7 shows an example of a graph of normalized array factor for a beamforming device according to this disclosure, such as the beamforming device shown in any of Figures 2-5. More specifically, the graph of Figure 7 shows, for each of first ports 1-9, the normalized array factor for a signal of 30 GHz applied to the port at a range of observation angles. The beam step size is around 6.6 degrees, the 3dB beamwidth is around 12.5 degrees, and the maximum beam cross-over level is around 1dB between adjacent beam ports. The resulting wideband isolation between adjacent ports is below around -17dB.

[0045] A beamforming apparatus or transceiver according to embodiments of this disclosure may be used in some examples in wireless communications apparatus. Examples of the wireless communication apparatus may include, for example, a base station, radio unit, wireless access point, a mobile phone, wifi terminal, wireless repeater, or any apparatus or device that may communicate wirelessly, such as a device or apparatus implementing a 3rd Generation Partnership Project (3GPP) wireless communication standard.

[0046] It should be noted that the above-mentioned examples illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative examples without departing from the scope of the appended claims. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim, “a” or “an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims below. Where the terms, “first”, “second” etc. are used they are to be understood merely as labels for the convenient identification of a particular feature. In particular, they are not to be interpreted as describing the first or the second feature of a plurality of such features (i.e., the first or second of such features to occur in time or space) unless explicitly stated otherwise. Steps in the methods disclosed herein may be carried out in any order unless expressly otherwise stated. Any reference signs in the claims shall not be construed so as to limit their scope.

Claims

Claims1. A transceiver (300, 400, 500) comprising: a beamforming device (200) comprising: a lens or passive beamforming network (202) having a plurality of first ports (204) and a plurality of second ports (206); and an antenna array comprising a plurality of antennas (208), wherein each of a plurality of the second ports is connected to a respective antenna of the plurality of antennas, and wherein each first port corresponds to a respective beam direction of a signal transmitted from and / or received at the antenna array; wherein the transceiver further comprises: at least one transmitter (304) having an output connected or connectable to a first one or more of the plurality of first ports; and at least one receiver (306) having an input connected or connectable to a second one or more of the plurality of first ports; and wherein the at least one transmitter and the at least one receiver are configured to simultaneously transmit at least one signal from the plurality of antennas and receive at least one signal from the plurality of antennas.

2. The transceiver of claim 1, wherein the lens or passive beamforming network (202) is configured such that, for each first port (204), a signal provided to the first port propagates to each second port (206) with a respective phase of the first signal.

3. The transceiver of claim 2, wherein the lens or passive beamforming network (202) is configured such that, for each first port (204), the respective phase of the signal at each second port (206) from the first port causes the signal to be transmitted in the respective beam direction for the first port.

4. The transceiver of any of claims 1 to 3, wherein the lens or passive beamforming network (202) is configured such that, for each of the plurality of the second ports (206), a phase of a signal at the second port from a selected one of the first ports (204) is dependent on the selected first port.

5. The transceiver of any of claims 1 to 4, wherein beams corresponding to adjacent first ports (204) at least partially overlap.

6. The transceiver of any of claims 1 to 5, comprising a multiplexer (302) configured to:connect the output of each of the at least one transmitter (304) to any selected first port (204) of the plurality of first ports; and connect the input of each of the at least one receiver (306) to any selected first port of the plurality of first ports.

7. The transceiver of any of claims 1 to 5, comprising a multiplexer (402) configured to: connect the output of each of the at least one transmitter (304) to any selected first port of a first subset (404) of the first ports (204); and connect the input of each of the at least one receiver (306) to any selected first port of a second subset (406) of the first ports, wherein the first subset is different to the second subset.

8. The transceiver of claim 7, wherein the first subset (404) and the second subset (406) include no common first port.

9. The transceiver of claim 7 or 8, wherein each first port (204) in the first subset (404) is adjacent to a first port in the second subset (406), and / or each first port in the second subset is adjacent to a first port in the first subset.

10. The transceiver of any of claims 1 to 9, wherein the at least one transmitter (304) comprises a plurality of transmitters having outputs connected or connectable to different first ports (204) of the plurality of first ports.

11. The transceiver of any of claims 1 to 10, wherein the at least one receiver (306) comprises a plurality of receivers having outputs connected or connectable to different first ports (204) of the plurality of first ports.

12. The transceiver of any of claims 1 to 11, wherein the output of the at least one transmitter (304) is connected or connectable to a different first port (204) than the input of the at least one receiver (306).

13. The transceiver of any of claims 1 to 12, wherein the lens or passive beamforming network (202) comprises a Rotman lens or Butler matrix.

14. The transceiver of any of claims 1 to 13, wherein the at least one transmitter (304) and the at least one receiver (306) are configured to operate in full duplex mode.

15. The transceiver of any of claims 1 to 14, wherein:the transmitter (304) is configured to transmit a first signal on a first beam using a first port (204) corresponding to a beam direction in a direction of a first wireless communications device; and the receiver (306) is configured to receive a second signal on a second beam using a first port corresponding to a beam direction in a direction of a second wireless communications device.

16. The transceiver of claim 15, wherein the first beam at least partially overlaps with the second beam or does not overlap with the second beam.

17. The transceiver of any of claims 1 to 14, wherein: the transmitter (304) is configured to transmit a first signal using a first port (204) corresponding to a beam direction in a direction of a first wireless communications device; and the receiver (306) is configured to receive a second signal using a first port corresponding to a beam direction in a direction of the first wireless communications device, wherein the first beam at least partially overlaps with the second beam.

18. The transceiver of claim 17, wherein the transmitter (304) is configured to transmit the first signal using one of the first ports (204) and the receiver (306) is configured to receive the second signal using a different one of the first ports.

19. The transceiver of any of claims 1 to 18, comprising self-interference cancellation (SIC) apparatus (312, 502) configured to attenuate a signal at the output of the at least one transmitter (304) and to provide the attenuated signal with a phase and / or time shift to the input or an output of the at least one receiver (306).

20. Wireless communications apparatus comprising the transceiver of any of claims 1 to 19.

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