A network-controlled repeater including a first transmission pathway for amplifying a first signal received from at least a first antenna port and transmitted by at least a second antenna port; a second transmission pathway for amplifying a second signal received from at least the second antenna port and transmitted by at least the first antenna port; means for self-interference cancelling including a feedback pathway to modify the first signal associated with the first transmission pathway; and a controller. The controller includes means for causing the first signal to be propagated and amplified along the first transmission pathway; means for causing the second signal to be propagated and amplified along the second transmission pathway; and means for causing a self-interference cancelling signal to be propagated along the feedback pathway to modify the first signal associated with the first transmission pathway. The second transmission pathway is reused for the feedback pathway.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No. 22216602.7, filed Dec. 23, 2022, the entire contents of which are incorporated herein by reference.

TECHNOLOGICAL FIELD

Examples of the disclosure relate to a network-controlled repeater.

BACKGROUND

A repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. A signal transmitted by a repeater can be received by the repeater leading to self-interference.

A repeater can be a bi-directional repeater that operates as a repeater in two directions. Such a bi-directional repeater comprises a first transmission pathway for amplifying a signal received from a first direction before re-transmission and a second transmission pathway for amplifying a signal received from a second direction before re-transmission.

In current radio telecommunication systems self-interference can be cancelled using digital processing to remove or reduce the effects of the self-interference. However, this uses significant digital processing resources that are not necessarily available at a repeater.

BRIEF SUMMARY

According to various, but not necessarily all, examples, there is provided a network-controlled repeater comprising:a first transmission pathway for amplifying a first signal received from at least a first antenna port and transmitted by at least a second antenna port;a second transmission pathway for amplifying a second signal received from at least the second antenna port and transmitted by at least the first antenna port;means for self-interference cancelling comprising:a feedback pathway to modify the first signal associated with the first transmission pathway; anda controller comprising:means for causing the first signal to be propagated and amplified along the first transmission pathway;means for causing the second signal to be propagated and amplified along the second transmission pathway; andmeans for causing a self-interference cancelling signal to be propagated along the feedback pathway to modify the first signal associated with the first transmission pathway;wherein the second transmission pathway is reused for the feedback pathway.

According to various, but not necessarily all, examples, the controller is configured to control a relative phase between the first signal and the self-interference cancelling signal.

According to various, but not necessarily all, examples, the controller is configured to control the relative phase between the first signal and the self-interference cancelling signal, wherein the control of the relative phase comprises controlling a phase of the first signal and/or a phase of the self-interference cancelling signal.

According to various, but not necessarily all, examples, the controller is configured to control a phase control means in the feedback pathway and/or is configured to control a phase control means in the transmission pathway.

According to various, but not necessarily all, examples, the controller is configured to control an amplitude of the self-interference cancelling signal in the feedback pathway.

According to various, but not necessarily all, examples, the controller is configured to independently control a relative phase between the first signal and the self-interference cancelling signal and an amplitude of the self-interference cancelling signal to produce self-interference cancelation.

According to various, but not necessarily all, examples, the controller is configured to control a relative phase between the first signal and the self-interference cancelling signal and an amplitude of the self-interference cancelling signal to optimise self-interference cancelation.

According to various, but not necessarily all, examples, the repeater is configured to receive a reference signal, and the controller is configured to control self-interference cancelation based on a comparison between the received reference signal and an expected reference signal.

According to various, but not necessarily all, examples, the network-controlled repeater further comprises at least a first antenna element and a second antenna element, and at least a first phase shifter and a second phase shifter, wherein the first phase shifter is configured to control a phase of at least a part of the first signal received by the first antenna element and/or is configured to control at least a part of the second signal transmitted by the first antenna element, and the second phase shifter is configured to control a phase of at least a part of the first signal transmitted by the second antenna element and/or at least a part of the second signal received by the second antenna element.

According to various, but not necessarily all, examples, the means for causing the first signal to be propagated and amplified comprises at least a first coupler and a second coupler, wherein the first coupler is shared between the first transmission pathway and the second transmission pathway and the second coupler is shared between the first transmission pathway and the second transmission pathway.

According to various, but not necessarily all, examples, the network-controlled repeater further comprises switching circuitry to enable alternate use of the first coupler for out-coupling from the first transmission pathway and in-coupling to the second transmission pathway and, synchronised, alternate use of the second coupler for in-coupling to the first transmission pathway and out-coupling from the second transmission pathway.

According to various, but not necessarily all, examples, the means for self-interference cancelling further comprises a second feedback pathway to modify the second signal associated with the second transmission pathway; wherein the controller further comprises means for causing a second self-interference cancelling signal to be propagated along the second feedback pathway to modify the second signal associated with the second transmission pathway; wherein the first transmission pathway is reused for the second feedback pathway.

According to various, but not necessarily all, examples, during a first time division duplex time slot, the first coupler is configured to out-couple a portion of the first signal into the feedback pathway from the first transmission pathway, and the second coupler is configured to in-couple at least a portion of a self-interference cancelling signal from the feedback pathway into the first transmission pathway and during a second time division duplex time slot, the second coupler is configured to out-couple a portion of the second signal into a second feedback pathway, and the first coupler is configured to in-couple at least a portion of a self-interference cancelling signal from the second feedback pathway into the second transmission pathway.

According to various, but not necessarily all, examples, the network-controlled repeater further comprises: a third transmission pathway for amplifying a third signal received from at least the first antenna port and transmitted by at least the second antenna port;a fourth transmission pathway for amplifying a fourth signal received from at least the second antenna port and transmitted by at least the first antenna port; andwherein the means for self-interference cancelling further comprises: a further feedback pathway to modify the third signal associated with the third transmission pathway;wherein the controller further comprises:means for causing the third signal to be propagated and amplified along the third transmission pathway;means for causing the fourth signal to be propagated and amplified along the fourth transmission pathway; andmeans for causing a further self-interference cancelling signal to be propagated along the further feedback pathway to modify the third signal associated with the third transmission pathway;wherein the fourth transmission pathway is reused for the further feedback pathway.

According to various, but not necessarily all, examples, there is provided a network-controlled repeater comprising:a transmission pathway for amplifying a signal received from at least a first antenna port and transmitted by at least a second antenna port;means for self-interference cancelling comprising: a feedback pathway to modify the signal associated with the transmission pathway; anda controller comprising:means for causing a signal to be propagated and amplified along the transmission pathway; andmeans for causing a self-interference cancelling signal to be propagated along the feedback pathway to modify the signal associated with the transmission pathway;wherein the means for self-interference cancelling are configured to control the phase of the signal associated with the transmission pathway and the amplitude of the self-interference cancelling signal to produce self-interference cancelation.

While the above examples of the disclosure and optional features are described separately, it is to be understood that their provision in all possible combinations and permutations is contained within the disclosure. It is to be understood that various examples of the disclosure can comprise any or all of the features described in respect of other examples of the disclosure, and vice versa. Also, it is to be appreciated that any one or more or all of the features, in any combination, may be implemented by/comprised in/performable by an apparatus, a method, and/or computer program instructions as desired, and as appropriate.

Similar reference numerals are used in the figures to designate similar features. For clarity, all reference numerals are not necessarily displayed in all figures.

DETAILED DESCRIPTION

FIG.1illustrates an example of a network100comprising a plurality of network nodes including terminal nodes110, access nodes120and one or more core nodes129. The terminal nodes110and access nodes120communicate with each other. The one or more core nodes129communicate with the access nodes120.

The network100is in this example a radio telecommunications network, in which at least some of the terminal nodes110and access nodes120communicate with each other using transmission/reception of radio waves.

The one or more core nodes129may, in some examples, communicate with each other. The one or more access nodes120may, in some examples, communicate with each other.

The network100may be a cellular network comprising a plurality of cells122each served by an access node120. In this example, the interface between the terminal nodes110and an access node120defining a cell122is a wireless interface124. In some examples, the wireless interface124comprises at least one repeater.

The access node120is a cellular radio transceiver. The terminal nodes110are cellular radio transceivers.

In the example illustrated the cellular network100is a third generation Partnership Project (3GPP) network in which the terminal nodes110are user equipment (UE) and the access nodes120are base stations.

In the particular example illustrated the network100is an Evolved Universal Terrestrial Radio Access network (E-UTRAN). The E-UTRAN consists of E-UTRAN NodeBs (eNBs)120, providing the E-UTRA user plane and control plane (RRC) protocol terminations towards the UE110. The eNBs120are interconnected with each other by means of an X2 interface126. The eNBs are also connected by means of the S1 interface128to the Mobility Management Entity (MME)129.

In other example the network100is a Next Generation (or New Radio, NR) Radio Access network (NG-RAN). The NG-RAN consists of gNode-Bs (gNBs)120, providing the user plane and control plane (RRC) protocol terminations towards the UE110. The gNBs120are interconnected with each other by means of an X2/Xn interface126. The gNBs are also connected by means of the N2 interface128to the Access and Mobility management Function (AMF).

A user equipment comprises a mobile equipment. Where reference is made to user equipment that reference includes and encompasses, wherever possible, a reference to mobile equipment.

FIG.2illustrates a first example of a network-controlled repeater200, according to embodiments of the disclosure. The repeater200forms part of a network100. In some examples, a network-controlled repeater200is a repeater200with advanced capabilities including beamforming and time division duplex (TDD) operation.

The network-controlled repeater200comprises a first antenna element213, a second antenna element214, a first transmission pathway202, a second transmission pathway204, and switching circuitry230.

The first transmission pathway202is configured to amplify a first signal220received from at least the first antenna element213and transmitted by at least the second antenna element214. A pathway is a path for an electronic signal. The pathway may be wired. A transmission pathway202,204is a pathway for a transmission signal. A transmission signal is a signal transmitted by the repeater200.

The second transmission pathway204is configured to amplify a second signal (no reference) received from at least the second antenna element214and transmitted by at least the first antenna element213.

The repeater200is configured to receive, amplify and forward the first signal220and the second signal. In some examples, the repeater200is an in-band repeater200and the first signal220and the second signal are in the same frequency band. The first signal220and the second signal may be analog signals. In some examples, the first transmission pathway202is for amplifying a first signal220having been received from at least a first antenna port and to be transmitted by at least a second antenna port; and the second transmission pathway204is for amplifying a second signal having been received from at least the second antenna port and to be transmitted by at least the first antenna port.

Antenna ports are a logical concept related to the physical layer (L1) and an antenna port can be considered a logical antenna. An antenna port represents a specific channel model. The first antenna port may map to a first antenna element. The second antenna port may map to a second antenna element. In some examples, an antenna port can map to more than one antenna element.

The switching circuitry230comprises a first switch232and a second switch234. The switching circuitry230switches between the first transmission pathway202and the second transmission pathway204, and between amplifying the first signal220and amplifying the second signal. The illustrated repeater200operates in TDD mode.

The illustrated repeater200is shown receiving a first signal220from the first antenna element213, propagating and amplifying the first signal220in the first transmission pathway202, and transmitting the first signal220using the second antenna element214.

Self-interference250occurs when the signal220transmitted by the transmitting antenna element214is received by the receiving antenna element213creating noise for the received first signal220. Self-interference250can occur via a number of different routes, for example, as illustrated inFIG.2including a direct route; a reflected self-interference signal involving one or more reflectors252, such as walls; and parasitic signal propagation within the repeater200.

FIG.3illustrates a second example of a network-controlled repeater200, according to embodiments of the disclosure. The second example of a network-controlled repeater200may comprise some or all of the features of the first example of a network-controlled repeater200.

The illustrated network-controlled repeater200comprises:a transmission pathway202for amplifying a signal220received from at least a first antenna port and transmitted by at least a second antenna port;means for self-interference cancelling comprising: a feedback pathway304to modify the signal220associated with the transmission pathway202; and a controller260.

The illustrated repeater200also comprises phase control means270and amplitude control means280.

The controller260comprises: means for causing a signal220to be propagated and amplified along the transmission pathway202; and means for causing a self-interference cancelling signal324to be propagated along the feedback pathway304to modify the signal220associated with the transmission pathway202.

A feedback pathway304is a pathway for the self-interference cancelling signal324. A feedback pathway304is configured to provide feedback to a transmission pathway202,204.

In some but not necessarily all examples, a transmission pathway that is not currently in use for transmission is reused for the feedback pathway.

In the illustrated example, the transmission pathway is the first transmission pathway202and the feedback pathway304is the second transmission pathway204. In this example, the signal is the first signal220in the first transmission pathway202.

However, in other example, the transmission pathway can be the second transmission pathway204and the feedback pathway can then be the first transmission pathway202. In this example, the signal is the second signal in the second transmission pathway204.

The feedback pathway304is configured to modify the signal220associated with the transmission pathway202to produce self-interference cancellation at least partially cancelling self-interference250. The self-interference250is caused by part of the signal220transmitted by a second antenna port being received from at least a first antenna port.

The illustrated repeater200comprises a first coupler342and second coupler344. The first coupler342is configured to out-couple a portion of the signal220into the feedback pathway304from the transmission pathway202. The second coupler344is configured to in-couple at least a portion of a self-interference cancelling signal324from the feedback pathway304into the transmission pathway202.

The controller260is configured to control a relative phase between the signal220and the self-interference cancelling signal324. The control of the relative phase comprises controlling a phase of the signal220and/or a phase of the self-interference cancelling signal324.

In some examples, the repeater200comprises phase control means270and the controller260is configured to control a phase control means270in the feedback pathway304and/or is configured to control a phase control means270in the transmission pathway202. In some examples, the phase control means270is positioned after the couplers342,342in the direction of the signal220.

In some but not necessarily all examples, the controller260is configured to control an amplitude of the self-interference cancelling signal324in the feedback pathway304. The controller260is configured to control an amplitude control means280in the feedback pathway304, wherein the amplitude control means280comprises at least one amplifier.

In some examples, the controller260is configured to independently control a relative phase between the signal220and the self-interference cancelling signal324and an amplitude of the self-interference cancelling signal324to produce self-interference cancelation. In some examples, the controller260is configured to control a relative phase between the signal220and the self-interference cancelling signal324and an amplitude of the self-interference cancelling signal324to optimise self-interference cancelation.

In some examples, the controller260is configured to control the phase of the signal220associated with the transmission pathway202and the amplitude of the self-interference cancelling signal324to produce self-interference cancelation.

In some examples, such as inFIGS.4A to8, the second transmission pathway204is reused for the feedback pathway304. As such, the feedback pathway304is the second transmission pathway204. In other examples, however, the feedback pathway304is separate to the second transmission pathway204, and the transmission pathway that is not currently in use for transmission is not reused for the feedback pathway.

FIGS.4A and4Billustrate a third example of a network-controlled repeater200, according to embodiments of the disclosure. The third example of a network-controlled repeater200may comprise some or all of the features of the first and second examples of a network-controlled repeater200.

FIG.4Aillustrates operation of the network-controlled repeater200at a first time, when the network-controlled repeater200amplifies a first signal220received from at least a first antenna port and transmitted by at least a second antenna port.FIG.4Billustrates operation of the network-controlled repeater200at a different second time when the network-controlled repeater200amplifies a second signal222received from at least the second antenna port and transmitted by at least the first antenna port. In some examples, at the first time the repeater200is operating in a downlink mode and at the second time the repeater200is operating in an uplink mode.

In this example, the network-controlled repeater200comprises a first transmission pathway202for amplifying a first signal220received from at least a first antenna port and transmitted by at least a second antenna port; a second transmission pathway204for amplifying a second signal222received from at least the second antenna port and transmitted by at least the first antenna port; means for self-interference cancelling comprising: a feedback pathway204to modify the first signal220associated with the first transmission pathway202; and a controller260(not illustrated).

The controller260comprising: means for causing the first signal220to be propagated and amplified along the first transmission pathway202(FIG.4A); means for causing the second signal222to be propagated and amplified along the second transmission pathway204(FIG.4B); and means for causing a self-interference cancelling signal324to be propagated along the feedback pathway204to modify the first signal220associated with the first transmission pathway202(FIG.4A). The second transmission pathway204is reused for the feedback pathway204.

In some examples, the means for self-interference cancelling further comprises a second feedback pathway202to modify the second signal222associated with the second transmission pathway204(FIG.4B); wherein the controller260further comprises means for causing a second self-interference cancelling signal326to be propagated along the second feedback pathway202to modify the second signal222associated with the second transmission pathway204; wherein the first transmission pathway202is reused for the second feedback pathway202.

By reusing the currently unused transmission pathway202,204for a feedback pathway204,202, self-interference cancelation can be achieved without dedicated self-interference cancelation components. Reducing the number of components leads to a less complex and less resource intensive repeater200.

InFIG.4A, the first signal220is propagated along the first transmission pathway202. A portion of the first signal220is out-coupled into the feedback pathway/second transmission pathway204from the first transmission pathway202. This creates the self-interference cancelling signal324. A portion of the self-interference cancelling signal324is in-coupled from the feedback pathway/second transmission pathway204into the first transmission pathway202. The first signal220propagates in a first direction, and the self-interference cancelling signal324propagates in a second direction opposite to the first direction. The first direction is from the first antenna port to the second antenna port, and the second direction is from the second antenna port to the first antenna port.

InFIG.4B, the second signal222is propagated along the second transmission pathway204. A portion of the second signal222is out-coupled into the second feedback pathway/first transmission pathway202from the second transmission pathway204. This creates the second self-interference cancelling signal326. A portion of the second self-interference cancelling signal326is in-coupled from the second feedback pathway/first transmission pathway202into the second transmission pathway204. The second signal222propagates in the second direction, and the second self-interference cancelling signal326propagates in the first direction opposite to the second direction.

FIG.5illustrates a fourth example of a network-controlled repeater200, according to embodiments of the disclosure. The fourth example of a network-controlled repeater200may comprise some or all of the features of the first, second and third examples of a network-controlled repeater200.

The illustrated repeater200comprises a first transmission pathway202, a second transmission pathway204, a first coupler342, a second coupler344, a first antenna panel511, a second antenna panel512and switching circuitry230.

The first transmission pathway202comprises at least a first amplifier503. The second transmission pathway204comprises at least a second amplifier505.

The means for causing the first signal220to be propagated and amplified comprises at least the first coupler342and the second coupler344. The first coupler342is shared between the first transmission pathway202and the second transmission pathway204. The second coupler344is also shared between the first transmission pathway202and the second transmission pathway204.

In the illustrated example, the first coupler342is positioned at a first end of the feedback pathway204and the second coupler344is positioned at a second end of the feedback pathway204. The illustrated first coupler342and second coupler344are directional couplers.

In some examples, the first coupler342is configured to couple a portion of the first signal220into the feedback pathway204to create the self-interference cancelling signal324, and the second coupler344is configured to couple at least a portion of the self-interference cancelling signal324into the first transmission pathway202to modify the first signal220.

In some but not necessarily all examples, the switching circuitry230operates in TDD mode. During a first time division duplex time slot, the first coupler342is configured to out-couple a portion of the first signal220into the feedback pathway204from the first transmission pathway202, and the second coupler344is configured to in-couple at least a portion of a self-interference cancelling signal324from the feedback pathway204into the first transmission pathway202. During a second time division duplex time slot, the second coupler344is configured to out-couple a portion of the second signal222into a second feedback pathway202, and the first coupler342is configured to in-couple at least a portion of a self-interference cancelling signal326from the second feedback pathway202into the second transmission pathway204. In some examples, the first time division duplex time slot is for downlink and the second time division duplex time slot is for uplink. Operation in these two time slots is illustrated inFIGS.6A and6Brespectively.

In some examples, the switching circuitry230enables alternate use of the first coupler342for out-coupling from the first transmission pathway202and in-coupling to the second transmission pathway204and, synchronised, alternate use of the second coupler344for in-coupling to the first transmission pathway202and out-coupling from the second transmission pathway204.

In some examples, the switching circuitry230is for switching between propagating the first signal220in a first direction, and propagating the second signal222in a second direction opposite to the first direction. The first direction is from the first antenna port215to the second antenna port216, and the second direction is from the second antenna port216to the first antenna port215.

In the illustrated example, in the first direction the second coupler344is positioned before the first coupler342, and the switching circuitry230comprises, at least one first switch232positioned before the second coupler344and at least one second switch234positioned after the first coupler342. The first switch232and second switch234are positioned outside the couplers342,344.

In the illustrated example, the switching circuitry230further comprises for each of the first transmission pathway202and the second transmission pathway204, at both ends of the first transmission pathway202and the second transmission pathway204, a switch533between a pathway to an antenna port215,216and a pathway to a terminator531. The terminator531can comprise a resistor. The terminators531are configured to reduce or eliminate reflections. In some examples, the switches232,234,532are radio frequency, RF, switches, such as single pole double throw (SPDT) switches.

The repeater200comprises a first antenna port215for at least a first antenna element213and a second antenna port216for at least a second antenna element214.

In some examples, the repeater200comprises at least a first phase shifter514and a second phase shifter524. The first phase shifter514is configured to control a phase of at least a part of the first signal220received by the first antenna element213and/or is configured to control at least a part of the second signal222transmitted by the first antenna element213. The second phase shifter524is configured to control a phase of at least a part of the first signal220transmitted by the second antenna element214and/or at least a part of the second signal222received by the second antenna element214. As such, the first phase shifter514is associated with the first antenna port215and the first antenna element213; and the second phase shifter524is associated with the second antenna port216and the second antenna element214. In some examples, the first phase shifter514and the second phase shifter524are for beamforming and may be vector modulators. The phase control means270ofFIG.3may comprise the first phase shifter514and/or the second phase shifter524ofFIG.5.

The first antenna panel511comprises the first antenna element213, the first antenna port215and the first phase shifter514. The second antenna panel512comprises the second antenna element214, the second antenna port216and the second phase shifter524.

In some examples, controlling the phase of the first signal220to optimise the self-interference cancelation is performed using at least a second phase shifter524. That is, controlling the phase of the first signal220to optimise the self-interference cancelation is performed using a phase shifter524associated with a transmitting antenna element214.

In some examples, the controller260is configured to control the phase of the first signal220downstream of the first coupler342and the second coupler344and/or downstream of the switching circuitry230. Downstream is further on in the first direction. The controller260is configured to control the phase of the first signal220after the couplers342,342and/or the switching circuitry230in the direction of the first signal220.

The relative phase differences between the phase-shifters514,524within an antenna panel511,512are used to control the beam configuration of the antenna array of antenna elements213,214.

The absolute phase of the transmitted signal220,222can be changed by changing the absolute phase on all the phase-shifters514,524, while maintaining their relative phase differences.

The illustrated first antenna panel511and second antenna panel512both comprise a plurality of amplifiers513,523; a respective amplifier513,523of the plurality of respective amplifiers513,523being configured to control an amplitude of a signal transmitted and/or received by the respective antenna element213,214. An antenna element213,214may use a different amplifier513,523when transmitting or receiving a signal. For example, a low noise amplifier513,523for reception, and a power amplifier513,523for transmission. The illustrated first antenna panel511and second antenna panel512also both comprise a splitter/combiner515,525to split or combine the respective signals transmitted and/or received by the respective antenna elements213,214.

In some examples, the first antenna element213is for connecting to a backhaul portion of a telecommunications network100, wherein the first signal220is a downlink signal received from at least the first antenna port215and transmitted onward via at least the second antenna port216, and the second antenna element214is for connecting to an access portion of the telecommunications network100wherein the second signal222is an uplink signal received from at least the second antenna port216and transmitted onward via at least the first antenna port215.

The backhaul portion of a telecommunications network100comprises at least one link between a core network of the telecommunications network100and the access portion of the telecommunications network100. The access portion of a telecommunications network100comprises at least one link between the backhaul portion of the telecommunications network100and terminal nodes/user equipment110of the telecommunications network100.

FIGS.6A and6Billustrate a fifth example of a network-controlled repeater200, according to embodiments of the disclosure. The fifth example of a network-controlled repeater200may comprise some or all of the features of the first, second, third and fourth examples of a network-controlled repeater200.

FIG.6Aillustrates the repeater200in a first mode in which the first signal220is propagated and amplified along the first transmission pathway202, and the first self-interference cancelling signal324is propagated and amplified along the second transmission pathway204. This may be during the first TDD time slot.FIG.6Billustrates the repeater200in a second mode in which the second signal222is propagated and amplified along the second transmission pathway204, and the second self-interference cancelling signal326is propagated and amplified along the first transmission pathway202. This may be during the second TDD time slot.

The fifth example of a network-controlled repeater200is similar to the fourth example of a network-controlled repeater200, with a number of differences.

In the illustrated example, the first transmission pathway202and the second transmission pathway204each comprise superheterodyne circuitry603,605. The superheterodyne circuitry603,605comprises amplifiers, mixers, oscillators610and filters. In some examples, the superheterodyne circuitry603,605comprises at least one low-pass filter or band-pass filter for down-conversion of the signal220,222, and at least one high-pass filter or band-pass filter for up-conversion of the signal220,222.

FIG.7illustrates a sixth example of a network-controlled repeater200, according to embodiments of the disclosure. The sixth example of a network-controlled repeater200may comprise some or all of the features of the first, second, third, fourth and fifth examples of a network-controlled repeater200.

The sixth example of a network-controlled repeater200is similar to the fifth example of a network-controlled repeater200, with a number of differences.

The illustrated repeater200is configured to amplify signals of two different characteristics, such as, for example, polarization. The polarization can be horizontal (H) and vertical (V) or, as another example, left and right circular. InFIG.7the repeater200comprises two sets of components. Components for one of the two signal characteristics include an ‘A’ at the end of the reference numeral; and components for the other of the two signal characteristics include a ‘B’ at the end of the reference numeral. In the illustrated example, the antenna ports215,216and antenna elements213,214are used for both polarisations.

In some examples, the repeater200further comprises: a third transmission pathway202B for amplifying a third signal received from at least the first antenna port215and transmitted by at least the second antenna port216; a fourth transmission pathway204B for amplifying a fourth signal received from at least the second antenna port216and transmitted by at least the first antenna port215. The means for self-interference cancelling further comprises: a further feedback pathway204B to modify the third signal associated with the third transmission pathway202B. The controller260further comprises: means for causing the third signal to be propagated and amplified along the third transmission pathway202B; means for causing the fourth signal to be propagated and amplified along the fourth transmission pathway204B; and means for causing a further self-interference cancelling signal324to be propagated along the further feedback pathway204B to modify the third signal associated with the third transmission pathway202B. In this example, the fourth transmission pathway204B is reused for the further feedback pathway204b. In some examples, the first and second signals220,222are of a first polarisation, and the third and fourth signals220,222are of a second polarisation different to the first polarisation.

The illustrated repeater200also comprises additional couplers342B,344B, an additional switching means230B, an additional splitter/combiner515B,525B, additional phase shifters514B,524B, and additional amplifiers513B,523B. There is one set of couplers342A,344A,342B,344B, switching means230A,230B, transmission pathways202A,204A,202B,204B, splitter/combiners515A,525A,515B,525B, phase shifters514A,524A,514B,524B, and amplifiers513A,523A,513B,523B for each of the two polorisations.

FIG.8illustrates a seventh example of a network-controlled repeater200, according to embodiments of the disclosure. The seventh example of a network-controlled repeater200may comprise some or all of the features of the first, second, third, fourth, fifth and sixth examples of a network-controlled repeater200.

In the illustrated repeater200, the controller260controls the phase of the feedback signal324using the phase shifter circuit813to optimise the self-interference cancelation. In some examples, the phase shifter circuit813comprises a bank of phase shifters. The illustrated phase shifter circuit813is shared by the first transmission pathway202and the second transmission pathway204. Second switching circuitry830is used to switch between the phase shifter circuit813being part of the first transmission pathway202, and the phase shifter circuit813being part of the second transmission pathway204. The second switching circuitry830can be considered to be part of the switching circuitry230. Second switching circuitry830is used to switch between the phase shifter circuit813controlling the phase of the self-interference cancelling signal324, and the phase shifter circuit813controlling the phase of the second self-interference cancelling signal326.

FIG.9illustrates a controller260of a network-controlled repeater200, according to embodiments of the disclosure. In this example, the controller260is configured to receive a control signal910and a reference signal920. The control signal910may be part of the first signal220and/or the second signal222. The reference signal920may be part of the first signal220and/or the second signal222.

The illustrated controller260comprises a decoder960for decoding control information910for the repeater200which is received by the repeater200. In some examples, the control information910is downlink control information910.

In some but now necessarily all examples, the repeater200is not regenerative and the decoder960is not configured to decode the entire first signal220.

The control signal910may comprise and/or indicate an expected reference signal915. In some examples, the repeater200is configured to receive the reference signal920, and the controller260is configured to control self-interference cancelation based on a comparison between the received reference signal920and an expected reference signal915. The controller260is configured to control phase and amplitude to optimize the self-interference cancelation based on the comparison between the received reference signal920and the expected reference signal915.

Providing better coverage enhances UE performance. Deploying additional cells would improve the coverage as well as the capacity in a certain area; however, such solutions are not the most preferred ones by operators due to the high cost and the limited backhaul options. Integrated access and backhaul (IAB) was introduced as a solution for coverage extension and capacity improvement, but the cost of it is high. On the other hand, another legacy solution for coverage extension has been the radio frequency (RF) repeaters200, which can be preferred by the operators specifically due to the low cost.

Specifically, due to the degraded propagation characteristics in frequency range2(FR2) of new radio (NR), providing the coverage in certain deployment scenarios could be challenging. For example, serving users around the corner of a building or providing outdoor-to-indoor coverage using FR2 band might not be possible. NR repeaters200would be useful for serving users in aforementioned use cases, because deploying base stations or IABs might not be the most cost-efficient solution for the operators.

RF repeaters200are non-regenerative type of relay nodes that amplify and forward everything that they receive, and can have no adaptive beamforming. Repeaters200are categorized based on their power classes (in the backhaul and access sides), and also based on the spectrum usage, e.g., single band, multi-band, etc. The main advantage of the RF repeaters200is that they are low cost, the ease of deployment, and no newly added latency. However, as they are simply configured to amplify the received signal, they might be amplifying the noise as well unintentionally. It is desirable to specify control functionalities to enable features for repeater200operation that are controlled by the network, allowing support for NR features like UE specific beam management and dynamic TDD. It is desirable that repeaters200are transparent to UE. A repeater200may be operating in FR2 with TDD and both outdoor and outdoor-to-indoor scenarios. A repeater200may be a single hop stationary repeater200.

A network-controlled repeater200amplifies the signal220it receives from the gNB and forwards it to the UE, and vice-versa. Mostly, the communication links established between the gNB-repeater and repeater-UE operate in the same band (i.e., in-band operation). This in-band repeater operation is spectrally efficient; however, it has a high risk of generating self-interference (SI)250to one side of the repeater200when the other side of it is transmitting. More specifically, the powerful transmit signal of the repeater200couples with the receiving antenna213, thus creating self-interference (SI)250. This coupling between the transmit and receive antennas213,214could be due to the reflection paths present in the environment/channel caused by objects252like walls and/or persons, and in some cases due to the direct path between the transmit and receive antennas213,214(depending on the repeater200implementation/deployment limitations). Additionally, parasitic signal propagation from the transmit path to the receive path could also cause SI.FIG.2shows a block diagram of a repeater200that operates in TDD mode, where a switch232,234is used to configure the direction of the signal path, i.e., either for downlink (DL) or uplink (UL). Here, the repeater200amplifies-and-forwards the downlink signal. Possible coupling between the transmit and receive antennas213,214for SI250are shown as direct (dark grey line), reflections (light grey line), and parasitic signal propagation (dashed lines), which are generating SI250at the receiving antenna.

One way of reducing SI250is by passive self-interference cancellation (SIC), i.e., by isolating the transmit and receive antennas of a repeater200by proper antenna deployment or implementation options. Simply, the idea here is to prevent leaking the transmitted RF signal to the receive antenna213. For example, by introducing a repeater200implementation/formfactor where the access side and the backhaul side are two separate modules. This approach will ensure some amount of isolation when those two modules are separated by a concrete wall. However, passive SIC might not be a viable option in all the cases, specifically when the access and backhaul antenna units have to be implemented in the same repeater200form-factor. In addition, the amount of isolation obtained via antenna isolation might not sufficiently reduce the SI250.

Active SIC can be used to further reduce the SI250of a repeater200. The idea here is to subtract any remaining SI250from the receive path using the knowledge of the transmit signal. Active SIC can be performed both in analog and digital domains. A repeater200is envisioned to be a low-cost and low-latency device compared to an IAB node to improve the coverage and gain attraction from the operators due to a lower unit cost. Hence, unlike in full-duplex radios, repeaters200will not have a baseband (BB) signal processing functionality to perform digital domain SIC. Specifically, a repeater200might not be implemented with a BB processing unit to decode the control signals to be forwarded to the UEs. However, in some examples, a light baseband signal processing unit is needed for the repeater200to decode the dedicated control information sent by the gNB in order to only amplify-and-forward when required. For example, in a very abstract level, such required control information at the repeater200could be beamforming configuration and TDD operation related information. But it is worth noting that such a BB processing unit960would be much simpler and cheaper than those required for an IAB node (which has decode-and-forward/regenerative capability). It would be orders of magnitude simpler and cheaper, since an IAB would require N USER parallel physical downlink shared channel (PDSCH) decoding capability whereas the repeater200would not decode PDSCH nor UE specific physical downlink control channel (PDCCH). A network-controlled repeater200would decode only the control information carrying signals and channels from the gNB. In short only 1 control channel and not N parallel data and control channels. An IAB is designed to support a capacity of x users in parallel thus it has a fixed processing power designed for a max number of users. Thus, one has to rely on analog domain SIC to further reduce the SI250of a repeater200.

Typically, analog SIC circuitry is implemented with an additional receiver RF front-end circuitry, and therefore incur relatively high cost, increased complexity, high component count, etc. Therefore, using additional analog SIC circuitry in a repeater200would increase the cost and complexity of implementation (compared to IAB), and hence reducing the attraction of operators for deploying repeater200to improve the coverage. Thus, a problem to be solved is how the analog domain SIC can be enabled in a repeater200to improve isolation, while keeping the complexity and cost of the repeater200low.

A proposed SIC solution is to re-use the existing unused signal path of the repeater200to couple a portion of the transmitted signal (the SI signal) to the active receiver path for analog signal cancellation. Instead of adding a new cancellation IC, we can enable SIC operation using the existing circuitries with few additional components (couplers and switches→no need to add amplifiers or phase shifters).

We propose an RF architecture for a repeater200which can perform SIC in RF domain. The main feature of the proposed architecture is that the repeater200uses/reuses many of the existing components from traditional repeater200RF architecture to perform the SI cancellation. This is achieved, in at least some examples, by the following steps:Use the absolute phase setting of the phase shifters514,524in the transmitting phased antenna array to adjust the phase of the feedback signal324,326to fit (−180°) the phase of the SI signal. The angular beam steering direction of the phased antenna array is dependent of the relative phase differences between the different elements213,214in the array. As such, adjusting the absolute phase of all the phase shifters513,514while keeping the relative phase difference constant, will not change the angular beam steering direction, but only change the absolute phase of the feedback signal324,326.Reuse the RF couplers342,344at each side of the repeater200(Tx & Rx) for each of the two RF paths202,204(downlink and uplink) by adding a novel switching/termination circuit230(232,234, four 533, the four 50Ω terminations531).Utilizing the unused RF path202,204(downlink or uplink) to feedback a portion of the transmitted signal220,222to the receiving point of the repeater200, while ensuring the correct amplified power level of the SI signal.

More details of the proposed architecture will be presented in the sequel. The implementation shown inFIG.5is for a four element antenna array, however any other number of elements213,214in the antenna array is also valid.

A potential reduction of additional components needed to include SIC on a traditional repeater RF architecture is shown in Table 1 (The numbers in Table 1 are for both signal characteristics, e.g. both polarizations):

TABLE 1Reducing of components for SIC onlegacy repeater RF architecture.Number of added componentsin novel andin traditional SICinventiveimplementationimplementationPhase Shifters40Amplifiers50Couplers84Switches08

A proposed novel SIC implementation for a repeater200does not need any addition of expensive active components (phase shifters & amplifiers), will reduce the number of needed RF couplers342,344by a factor of two, at the expense of adding eight single throw double pole (STDP) switches. This is a significant improvement in cost, complexity and required dye size.

A SIC process flow is presented below. Note that in this flow, it is assumed that the repeater200receives downlink signal from the gNB via a first antenna panel511, and amplify-and-forward the DL signal via a second antenna panel522to the repeater200.Step 1 The repeater200is already in a radio resource control (RRC) connected state, and a suitable Backhaul beam has been selected for the repeater200to connect with the gNB and a suitable Access beam has been selected for connect to a UE.Step 2 The repeater200will wait for the next scheduled slot to be repeatedStep 3 Has the Backhaul beam or the Access beam been changed? A change in the Access beam can be due to movement of a connected UE or slot allocations for different UEs connect through different Access Beams.If ‘Yes’, the repeater200will continue to Step 4.If ‘No’, the repeater200will continue to Step 6.Step 4 The repeater200will re-initialize the SIC procedure, including the power levels and the phase offset, to adapt to the new beam configuration and thereby new feedback coupling.Step 5 The repeater200performs fine tuning of the phase and power levels for optimizing the SIC performance.Step 6 The repeater200checks if the direction of repeated signal220has been changed (A change between DL and UL).If ‘Yes’, the repeater200will continue to Step 7.If ‘No’, the repeater200will continue to Step 5.Step 7 Check which antenna panel511,512to be used for receiving the signal220from gNB or UE. Based on the assumption, the first antenna panel511is used to receive from gNB and the second antenna panel512is used to receive from the UE.If ‘the first antenna panel’ then the repeater200will continue to Step 8.If ‘the second antenna panel’ the repeater200will continue to Step 9.Step 8 Repeater200receives signal220from the gNB in the DL direction from the first antenna panel511, and transmit it to the UE via the second antenna panel512. A portion of the transmitted signal220is coupled with RF coupler344back to RF coupler342for SIC operation. Upon completion of Step 8, go back to Step 5 to proceed with the SIC fine tuning and then wait for the next slot/symbol (Step 2). Changing the direction of the repeated signal at the repeater200will not affect the overall SIC settings, since the feedback coupling can be considered reciprocal, so SIC re-initialization is not required.Step 9 Repeater200receives signal222from UE in the UL direction from the second antenna panel512, and transmit it the gNB via the first antenna panel511. A portion of the transmitted signal222is coupled with RF coupler342back to RF coupler344for SIC operation. Upon completion of Step 9 go back to Step 5 to proceed with the SIC fine tuning and then wait for the next slot/symbol (Step 2). Changing the direction of the repeated signal at the repeater200will not affect the overall SIC settings, since the feedback coupling can be considered reciprocal, so SIC re-initialization is not required.

The proposed solution utilizes the unused signal path of the repeater200(DL or UL path or both) to send a replica of the SI signal to the receive input. Existing “unused” circuitry and components are used whereby SIC features are enabled with only minor additional repeater hardware complexity. Using the absolute phase values of the antenna array beam steering phase shifters514,524for SIC, by adjusting the phase of the radiated feedback signal. This process can be symmetrically performed in both DL and UL directions. Directional couplers342,344are shared and the SIC direction is controlled by use of RF switches232,234,533.

In other repeaters200a dedicated SIC feedback path, which needs additional phase shifter and amplifier circuitry, is needed to perform SIC operation. The proposed SIC enabled architecture is adding two RF couplers, four SPDT switches and four terminations, which could be included in the SPDT switches. The proposed architecture uses existing phase shifter and amplifier circuitry.

In the following the signal flow is described and how the SIC feedback signal324,326can be injected to the directional coupler342,344. The repeater200architecture shown inFIG.6Ais configured to receive a signal220from the backhaul side at the first antenna panel511, amplify the received signal and repeat it on the access side at the second antenna panel512.

The signal220is received with the best configured beam at the first antenna panel511, combined and switched to the repeater200backhaul→access (B→A) path by controlling switches533. On the other side, switches533are configured to direct signal220to access side via the second antenna panel512.

A coupled feedback version of the transmitted signal220at the access side will be present at the backhaul side, with a certain amplitude and phase, depending on the environmental properties of the channel between the access side and the backhaul side. This feedback signal can be removed by applying the same signal at the backhaul side with the same amplitude and 180° out of phase, which can be achieved in the following way:

A switch533on the access side is configured for termination, whereby the RF coupler344will direct a portion (for example −20 dB) of the signal220to the access→backhaul (A→B) path. A switch533on the backhaul side is configured for termination, whereby the RF coupler342will direct a portion (for example −20 dB) of the SIC feedback signal to the B→A path. The amplifier505in the A→B path is used to adaptively adjust the amplitude level of the SIC feedback signal to the correct level, to match the level of the coupled feedback signal at RF coupler342.

The phase shifters524are used to adaptively adjust the phase of the coupled feedback signal, so that it will be 180° out of phase at RF coupler342.

An identical process can be carried out for a signal222received from the reversed direction as described below and shown inFIG.6B.

The signal222is received with the best configured beam at the second antenna panel512, combined and switched to the repeater200A→B path by controlling switches232,234,533. Switches232,234,533are configured to direct the signal222to backhaul side via the first antenna panel511.

A switch533on the backhaul side is configured for termination, whereby the RF coupler344will direct a portion (for example −20 dB) of the signal222to the B→A path. A switch533on the access side is configured for termination, whereby the RF coupler342will direct a portion (for example −20 dB) of the SIC feedback signal326to the A→B path. The amplifier503in the B→A path is used to adaptively adjust the amplitude level of the SIC feedback signal to the correct level, to match the level of the coupled feedback signal at RF coupler344. The phase shifters514are used to adaptively adjust the phase of the coupled feedback signal, so that it will be 180° out of phase at RF coupler344.

The implementation of the phase shifters524and RF couplers342,344needed for SIC in a repeater200architecture as shown inFIGS.5,6A and6Bcan be done in different alternative ways:As an alternative to using the absolute phases values at the antenna panels511,512, the phase adjustments for the SIC signal could be done in the intermediate frequency domain as shown inFIG.8.Separate RF couplers342,344could also be used instead of shared couplers342,344.

The phase shifter circuit813is used to modify the phase as required before the SIC feedback signal324,326is being injected to the directional coupler342,344to perform analog SIC. The phase shifter circuit813can be implemented as a bank of phase shifters. In practice, the channel202,204between the transmit and receive antennas (i.e., the feedback channel202,204) may be a time varying channel. Hence, the phase and amplitude of the SIC signal324,326must be carefully adjusted to match with the time varying feedback channel. The phase shifter circuit813can be implemented by use of a vector modulator.

The following advantages are provided:Reusing the existing RF architecture to perform SIC.Low cost, reduced complexity, and simple implementation of SIC enabled repeater200.An added isolation of, for example, up to 20 to 30 dB. Especially for the more challenging case where the repeater200is implemented as a single enclosure.Antenna module frequency selectivity help to protect the RF coupler circuitry from in band or out off band blocking signals that may disturb or even saturate the feedback path.

FIG.10illustrates an example of a controller260suitable for use in a repeater200. Implementation of a controller260may be as controller circuitry. The controller260may be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware).

As illustrated inFIG.10the controller260may be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program1006in a general-purpose or special-purpose processor1002that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor1002.

The processor1002is configured to read from and write to the memory1004. The processor1002may also comprise an output interface via which data and/or commands are output by the processor1002and an input interface via which data and/or commands are input to the processor1002.

The memory1004stores a computer program1006comprising computer program instructions (computer program code) that controls the operation of the apparatus200when loaded into the processor1002. The computer program instructions, of the computer program1006, provide the logic and routines that enables the apparatus to perform the methods illustrated in the accompanying figures. The processor1002by reading the memory1004is able to load and execute the computer program1006.

As illustrated inFIG.11, the computer program1006may arrive at the apparatus200via any suitable delivery mechanism1008. The delivery mechanism1008may be, for example, a machine readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a record medium such as a Compact Disc Read-Only Memory (CD-ROM) or a Digital Versatile Disc (DVD) or a solid-state memory, an article of manufacture that comprises or tangibly embodies the computer program1006. The delivery mechanism may be a signal configured to reliably transfer the computer program1006. The apparatus200may propagate or transmit the computer program1006as a computer data signal.

The computer program instructions may be comprised in a computer program, a non-transitory computer readable medium, a computer program product, a machine readable medium. In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

Although the memory1004is illustrated as a single component/circuitry it may be implemented as one or more separate components/circuitry some or all of which may be integrated/removable and/or may provide permanent/semi-permanent/dynamic/cached storage.

Although the processor1002is illustrated as a single component/circuitry it may be implemented as one or more separate components/circuitry some or all of which may be integrated/removable. The processor1002may be a single core or multi-core processor.

In some examples, a network-controlled repeater200comprises: a first transmission pathway202for amplifying a first signal220received from at least a first antenna port215and transmitted by at least a second antenna port216; a second transmission pathway204for amplifying a second signal222received from at least the second antenna port216and transmitted by at least the first antenna port215; a feedback pathway204to modify the first signal220associated with the first transmission pathway202; and a controller260. The controller260comprises: at least one processor1002; and at least one memory1004including computer program code1006, the at least one memory1004and the computer program code1006configured to, with the at least one processor1002, cause the controller260at least to perform: causing the first signal220to be propagated and amplified along the first transmission pathway202; causing the second signal222to be propagated and amplified along the second transmission pathway204; and causing a self-interference cancelling signal324to be propagated along the feedback pathway304to modify the first signal220associated with the first transmission pathway202; wherein the second transmission pathway204is reused for the feedback pathway304.

In some examples, a network-controlled repeater200comprises: a transmission pathway202for amplifying a signal220received from at least a first antenna port215and transmitted by at least a second antenna port216; a feedback pathway304to modify the signal220associated with the transmission pathway202; and a controller260. The controller260comprises: at least one processor1002; and at least one memory1004including computer program code1006, the at least one memory1004and the computer program code1006configured to, with the at least one processor1002, cause the controller260at least to perform: causing a signal220to be propagated and amplified along the transmission pathway202; causing a self-interference cancelling signal324to be propagated along the feedback pathway304to modify the signal220associated with the transmission pathway202; and controlling the phase of the signal220associated with the transmission pathway202and the amplitude of the self-interference cancelling signal324to produce self-interference cancelation.

Components may be operationally coupled and any number or combination of intervening elements can exist (including no intervening elements).

In some but not necessarily all examples, the apparatus200is configured to communicate data from the apparatus200with or without local storage of the data in a memory1004at the apparatus200and with or without local processing of the data by circuitry or processors at the apparatus200.

In this description, the wording ‘couple’ and its derivatives mean operationally coupled. It should be appreciated that any number or combination of intervening components can exist (including no intervening components), i.e., so as to provide direct or indirect coupling. Any such intervening components can include hardware and/or software components.

The above description describes some examples of the present disclosure however those of ordinary skill in the art will be aware of possible alternative structures and method features which offer equivalent functionality to the specific examples of such structures and features described herein above and which for the sake of brevity and clarity have been omitted from the above description. Nonetheless, the above description should be read as implicitly including reference to such alternative structures and method features which provide equivalent functionality unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure.