Beam steering device and method

Abstract

An apparatus and method for beam steering is disclosed. The apparatus comprises a beamformed signal generator configured to generate a beamformed signal for application to at least one of amplitude and phase shift circuits associated with an antenna array to provide a radiation pattern. A determining component is provided configured to determine a signal strength of interfering signals received at the antenna array within a user equipment and to determine a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals. A comparator is provided configured to compare the dominant interference ratio to a predetermined ratio value and to generate a control signal for controlling the beamformed signal generator to generate a radiation pattern comprising a beam and at least one steered null in the event that the dominant interference ratio exceeds the predetermined ratio value.

Description

TECHNICAL FIELD

[0001] Various example embodiments relate to methods and apparatus for beamforming at a portable electronic device such as a user equipment (UE). BACKGROUND

[0002] Beamforming or steering can be used with an antenna array comprising a plurality of antenna elements to improve reception of a desired signal. In the presence of interference from other signals, then generation of one or more steered nulls (i.e. parts of the radiation pattern around the UE with directionally controlled low signal strength) can help improve the signal to interference plus noise ratio (SINR) at the UE. However, such beam steering is complex and has processing power, power and time overheads associated with it, and there can be situations where the beam steering does not provide much if there is any signal improvement. Furthermore, where conditions around the antenna array are dynamic, then the preferred radiation pattern can change.

[0003] It would be desirable to provide a beam steering apparatus and method that addresses at least some of these problems. SUMMARY

[0004] The scope of protection sought for various embodiments of the present application is set forth by the independent claims. Embodiments / examples and features described in this specification that are not within the scope of the independent claims if any, are to be interpreted as examples useful for understanding the various embodiments of the present application.

[0005] According to a number of but not necessarily all embodiments of the present application, according to a first aspect there is provided an apparatus comprising: a beamforming signal generator configured to generate a beamforming signal for application to at least one of amplitude and phase shift circuits associated with an antenna array for providing a radiation pattern; and a determining component configured to determine a signal strength of an interfering signal received at the antenna array within a user equipment, and to determine a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; and a comparator configured to compare the dominant interference ratio to a predetermined ratio, and to generate a control signal for controlling the beamforming signal generator to generate a radiation pattern comprising a beam and at least one steered null in the event that the dominant interference ratio exceeds the predetermined ratio.

[0006] Beamforming or steering can be used with one or more antenna arrays comprising multiple antenna elements to improve reception of a desired signal. In the presence of interference from other signals, then the generation of one or more steered nulls (i.e. parts of the radiation pattern around a UE with directionally controlled low signal strength) can help improve the signal to interference plus noise ratio. However, the generation of such steered nulls is not without overhead and can only provide an effective signal to noise ratio improvement for certain interference patterns. The inventors have recognised that the dominant interference ratio is a good indicator of how much the signal to noise ratio level can be improved with one or more steered nulls and, as such, embodiments determine the dominant interference ratio and use this as a factor in deciding whether to provide at least one steered null.

[0007] In some embodiments, the apparatus comprises a plurality of antenna arrays, the beamformed signal generator is configured to generate a beamformed signal for application to at least one of amplitude and phase shift circuits associated with the plurality of antenna arrays to provide a radiation pattern.

[0008] In some embodiments, there is only one steered null.

[0009] In some embodiments, the one steered null is directed towards the strongest interference.

[0010] In some embodiments, the comparator is further configured to generate a control signal for controlling the beamformed signal generator to generate a radiation pattern comprising a beam and no steered nulls in response to the dominant interference ratio being less than the predetermined ratio.

[0011] In some embodiments, the determining means is further configured to determine a signal to interference plus noise ratio and generate a control signal for controlling the beamformed signal generator to generate a radiation pattern comprising a beam and no steered nulls in response to the signal to interference plus noise ratio being greater than a predetermined value.

[0012] In some embodiments, the determining means is further configured to not determine the signal strength of the interference signal in response to the signal to interference plus noise ratio being greater than a predetermined value.

[0013] According to a number, but not necessarily all, embodiments of the present application there is provided an apparatus comprising: a beamformed signal generator configured to apply a beamformed signal to amplitude and phase shift circuits associated with an antenna array to generate a radiation pattern comprising a beam and at least one steered null at the antenna array; and means configured to detect at least one condition change at the user equipment affecting a null in the radiation pattern and modify the beamformed signal to reduce the change in the at least one steered null.

[0014] In some embodiments, the monitoring component configured to detect at least one condition change comprises a standing wave detector.

[0015] In some embodiments, the apparatus further comprises a monitoring component configured to monitor, at the user equipment, at least one condition change affecting a null in a radiation pattern at the user equipment when the beamformed signal applied to the amplitude and phase circuitry comprises a beamformed signal for generating a radiation pattern comprising a beam and at least one steered null, the monitoring component configured to generate, in response to detecting the at least one condition change, a control signal to apply to the beamformed signal generator to control the beamformed signal generator to modify the beamformed signal to at least partially compensate for a change in the at least one steered null in the radiation pattern.

[0016] In some embodiments, the beamformed signal generator is configured to modify the beamformed signal to generate a plurality of updated radiation patterns by a plurality of changes in an angular position of the at least one steered null; the determining component is configured to determine a preferred angular position of the at least one steered null by determining the received power, the signal-to-interference-plus-noise ratio and the dominant interference ratio for the plurality of updated radiation patterns.

[0017] In some embodiments, the monitoring component is configured to detect the at least one condition change from at least one of: a decrease in received power detected at the antenna array; a decrease in signal-to-interference-plus-noise ratio; and an increase in the dominant interference ratio.

[0018] In some embodiments, the monitoring component is configured to detect the at least one condition change from a decrease in received power detected at the antenna array; a decrease in signal-to-interference-plus-noise ratio; and an increase in the dominant interference ratio.

[0019] In some embodiments, the monitoring component is configured to detect the at least one condition change by detecting at least one of: a change in user proximity from a proximity sensor, and a change in operating conditions of at least one of a plurality of predetermined components within the user equipment.

[0020] In some embodiments, the change in operating conditions comprises a change in state of at least one of a plurality of predetermined components within the user equipment. In some embodiments, the change in state comprises activation or deactivation of a component.

[0021] In some embodiments, the apparatus further comprises a database for storing a plurality of signal vectors for application to at least one of the amplitude and phase shift circuits to generate different radiation patterns; the beamforming signal generator is configured to generate the beamforming signal by selecting one of the plurality of signal vectors.

[0022] In some embodiments, the beamforming signal generator is configured to modify the beamforming signal to at least partially compensate for a change in the at least one steered null in the radiation pattern by selecting an updated value from the database and determining from the determining component whether the signal to interference plus noise ratio is increased, and without discarding the selected value and selecting a further value.

[0023] In some embodiments, the beamforming signal generator is configured to modify the beamforming signal by selecting a modified database entry related to the detected predetermined operational change.

[0024] In some embodiments, the beamforming signal generator is configured to modify the beamforming signal to at least partially compensate for a change in the at least one steered null in the radiation pattern by applying an algorithm related to the determined change in operational conditions to the beamforming signal and determining from the determining component whether the signal to interference plus noise ratio is increased. In the event that the signal to interference plus noise ratio is not increased, the updated beamforming signal is discarded and in some cases a different algorithm is applied.

[0025] In some embodiments, the monitoring component, determining component, beamforming signal generator and comparator comprise: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: determining a signal strength of an interfering signal received at an antenna system within a user equipment; determining a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; and comparing the dominant interference ratio to a predetermined ratio value; and in the event that the dominant interference ratio exceeds the predetermined ratio value, generating a beamforming signal for application to at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and at least one steered null.

[0026] According to various, but not necessarily all, embodiments of the invention there is provided a user equipment comprising: an antenna array comprising a plurality of antenna elements; amplitude and phase shift circuits associated with the antenna elements of the antenna array; and an apparatus according to the first or second aspect.

[0027] According to various, but not necessarily all, embodiments of the application, according to a fourth aspect there is provided a method comprising: determining a signal strength of interfering signals received at an antenna array within a user equipment; determining a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; and comparing the dominant interference ratio to a predetermined ratio value; and generating a beamforming signal for application to at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and at least one steered null, in the event that the dominant interference ratio exceeds the predetermined ratio value.

[0028] In some embodiments, the method further comprises: in the event that the dominant interference ratio is less than the predetermined value, generating the beamforming signal for application to the at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and no steered null.

[0029] In some embodiments, the method further comprises an initial step of determining a signal to interference plus noise ratio, and in the event that the signal to interference plus noise ratio is greater than a predetermined value, not performing the step of the method of determining the signal strength of interfering signals, and generating the beamforming signal for application to the at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and no steerable null.

[0030] According to various, but not necessarily all, embodiments of the application, according to a fifth aspect there is provided a method comprising: generating a beamforming signal for application to at least one of amplitude and phase shift circuits associated with an antenna array to generate a radiation pattern comprising a beam and at least one steered null at the antenna array; detecting at least one condition change at the user equipment affecting a null in the radiation pattern and modifying the beamforming signal to reduce the change in the at least one steered null.

[0031] In some embodiments, the method further comprises: while the beamforming signal applied to the at least one of the amplitude and phase shift circuits generates a radiation pattern comprising a beam and at least one steered null, monitoring at the user equipment for at least one condition change affecting a null in the radiation pattern at the user equipment; and in response to detecting the at least one condition change, modifying the beamforming signal to at least partially compensate for the change in the at least one steered null in the radiation pattern.

[0032] In some embodiments, the step of detecting the at least one condition change affecting the radiation pattern comprises detecting at least one of: a reduction in received power at the antenna array; a reduction in signal to interference plus noise ratio; and an increase in the dominant interference ratio.

[0033] In some embodiments, in response to detecting the at least one condition change, an updated beamforming signal is generated, which is configured to change the angular position of the at least one null, and the preferred angular position of the at least one null is determined by detecting the received power, the signal-to-interference-plus-noise ratio and the dominant interference ratio of the updated signal.

[0034] In some embodiments, the method further comprises determining the at least one condition triggering the change of the radiation pattern by determining at least one of a change in proximity of a user and a change in operating conditions of at least one of a plurality of predetermined components within the user equipment.

[0035] In some embodiments, the method further comprises determining the at least one operating condition triggering the change of the radiation pattern by detecting a predetermined operating change of at least one of a plurality of predetermined components within the user equipment.

[0036] In some embodiments, the beamforming signal is selected from a database storing beamforming signal vectors for application to at least one of the amplitude and phase shift circuits to generate different radiation patterns.

[0037] In some embodiments, the step of modifying the beamforming signal comprises selecting a further value from the database and determining whether the signal-to-interference-plus-noise ratio is increased, and if not, discarding the selected value and selecting a further value.

[0038] In some embodiments, the step of modifying the beamforming signal comprises selecting a modified database entry related to the detected predetermined operating change.

[0039] In some embodiments, the step of modifying the beamforming signal comprises applying an algorithm related to the determined operating condition change to the beamforming signal.

[0040] According to various, but not necessarily all, embodiments of the invention there is provided a computer program comprising instructions for causing an apparatus to perform the method according to the fourth or fifth aspect.

[0041] According to a number, but not necessarily all, embodiments of the present application, there is provided, in accordance with a seventh aspect, an apparatus comprising: a beamforming signal generator configured to generate a beamforming signal for application to at least one of amplitude and phase shift circuits associated with an antenna array to provide a radiation pattern; and determining circuitry configured to determine signal strengths of interfering signals received at the antenna array within a user equipment and to determine a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; and a comparator configured to compare the dominant interference ratio to a predetermined ratio value and to generate a control signal for controlling the beamforming signal generator to generate a radiation pattern comprising a beam and at least one steered null in the event that the dominant interference ratio exceeds the predetermined ratio.

[0042] In some embodiments, the comparator is further configured to generate a control signal for controlling the beamforming signal generator to generate a radiation pattern comprising a beam and no steered nulls in response to the dominant interference ratio being less than the predetermined ratio.

[0043] In some embodiments, the determining circuitry is further configured to determine a signal to interference plus noise ratio and to generate a control signal for controlling the beamforming signal generator to generate a radiation pattern comprising a beam and no steered nulls in response to the signal to interference plus noise ratio being greater than a predetermined value.

[0044] In some embodiments, the determining circuitry is further configured to not determine the signal strengths of the interfering signals in response to the signal to interference plus noise ratio being greater than a predetermined value.

[0045] According to a number, but not necessarily all, embodiments of the present application, there is provided, in accordance with an eighth aspect, an apparatus comprising: a beamforming signal generator configured to apply a beamforming signal to amplitude and phase shift circuits associated with an antenna array to generate a radiation pattern comprising a beam and at least one steered null at the antenna array; and circuitry configured to detect at least one condition change affecting a null in the radiation pattern at the user equipment and to modify the beamforming signal to reduce the change in the at least one steered null.

[0046] In some embodiments, the apparatus further comprises: monitoring circuitry configured to monitor, at the user equipment, at least one condition change affecting a null in a radiation pattern at the user equipment when the beamformed signal applied to the amplitude and phase shift circuitry comprises a beamformed signal for generating a radiation pattern comprising a beam and at least one steered null; the monitoring circuitry configured to generate, in response to detecting the at least one condition change, a control signal for application to the beamformed signal generator to control the beamformed signal generator to modify the beamformed signal to at least partially compensate for a change in the at least one steered null in the radiation pattern.

[0047] In some embodiments, the beamformed signal generator is configured to modify the beamformed signal to generate a plurality of updated radiation patterns by a plurality of changes in an angular position of the at least one steered null; the determining circuitry is configured to determine a preferred angular position of the at least one steered null by determining the received power, the signal-to-interference-plus-noise ratio and the dominant interference ratio for the plurality of updated radiation patterns.

[0048] In some embodiments, the monitoring circuitry is configured to detect the at least one condition change from at least one of: a decrease in received power detected at the antenna array; a decrease in signal-to-interference-plus-noise ratio; and an increase in the dominant interference ratio.

[0049] In some embodiments, the monitoring circuitry is configured to detect the at least one condition change from a decrease in received power detected at the antenna array; a decrease in signal-to-interference-plus-noise ratio; and an increase in the dominant interference ratio.

[0050] In some embodiments, the monitoring circuitry is configured to detect the at least one condition change by detecting at least one of: a change in user proximity from a proximity sensor, and a change in operating condition of at least one predetermined component of a plurality of predetermined components within the user equipment.

[0051] In some embodiments, the change in operating condition comprises a change in state of at least one predetermined component of a plurality of predetermined components within the user equipment. In some embodiments, the change in state comprises activation or deactivation of a component.

[0052] In some embodiments, the apparatus further comprises a database for storing a plurality of signal vectors for application to at least one of the amplitude and phase shift circuitry to generate different radiation patterns; the beamformed signal generator is configured to generate the beamformed signal by selecting one of the plurality of signal vectors.

[0053] In some embodiments, the beamformed signal generator is configured to modify the beamformed signal to at least partially compensate for the change in the at least one steered null in the radiation pattern by selecting an updated value from the database and determining from the determination circuitry whether the signal-to-interference-plus-noise ratio is increased, and if not discarding the selected value and selecting a further value.

[0054] In some embodiments, the beamformed signal generator is configured to modify the beamformed signal by selecting a modified database entry related to the detected predetermined operational change.

[0055] In some embodiments, the beamformed signal generator is configured to modify the beamformed signal to at least partially compensate for the change in the at least one steered null in the radiation pattern by applying an algorithm related to the determined change in operational conditions to the beamformed signal and determining from the determination circuitry whether the signal-to-interference-plus-noise ratio is increased. In case the signal-to-interference-plus-noise ratio is not increased, the updated beamformed signal is discarded and in some cases a different algorithm is applied.

[0056] In some embodiments, the determination circuitry comprises at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform.

[0057] Further specific and preferred aspects are set out in the appended dependent and independent claims. Features of dependent claims can be suitably combined with features of the independent claims, as appropriate, and in combinations other than those explicitly stated in the claims.

[0058] Where apparatus features are described as operable to provide functionality, it will be appreciated that this includes apparatus features which are provided for the purpose of providing that functionality or which are adapted to provide that functionality. BRIEF DESCRIPTION OF DRAWINGS

[0059] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0060] Figure 1 A flowchart illustrating a main interference ratio (DIR) based beam nulling and standing wave compensation scheme of an embodiment is shown;

[0061] Figure 2 A standing wave detector unit is shown schematically;

[0062] Figure 3 A database of codebook entries and associated radiation patterns is shown schematically;

[0063] Figure 4 An example showing the impact of a standing wave on nulls in the radiation pattern around a user equipment;

[0064] Figure 5 An example showing the impact of null position and loss of nulling due to standing waves;

[0065] Figure 6 A database showing pre-computed relationships between standing wave sources and associated codebook entries;

[0066] Figure 7 An example showing selection of codebook entries for each null and offset probability of the best codebook entry;

[0067] Figure 8 An example showing results of a recent codebook search; and

[0068] Figure 9 A user equipment according to an embodiment is shown. DETAILED DESCRIPTION

[0069] Before discussing the example embodiments in more detail, first an overview will be provided.

[0070] An antenna array formed of multiple antenna elements can have control circuitry associated with them that controls the phase shift and / or amplitude of the signals received from each antenna element so that the received signals interfere constructively or destructively with each other and in this way controls the radiation pattern seen by the antenna array. This is known as beamforming or spatial filtering and is a signal processing technique used in sensor arrays for directional signal transmission or reception. This directional transmission or reception is achieved by combining the elements in the antenna array in such a way that signals at a particular angle experience constructive interference (beam direction) while other signals experience destructive interference (null direction). To achieve spatial selectivity, beamforming can be used at both the transmit and receive ends. The improvement compared to omnidirectional reception / transmission is known as the directivity of the array.

[0071] In practice, the radiation pattern can be controlled to provide a beam of strong signals in one or more directions and a steered null in which there is no or limited radiation in other directions. This can be used to steer the beam towards a desired signal source while the null can be steered towards one or more interference sources.

[0072] For example, a UE operating in the 5G NR millimeter band(s) can have one or more antenna arrays that can have dynamic beam steering to reduce the level of interference received at the UE and improve radio link performance by controlling the shape of the radiation pattern produced by the UE.

[0073] The optimal or improved radiation pattern will depend on the signal received at the user equipment, in particular the strength of the interfering signals, the number of interfering signals and the signal to interference plus noise ratio. When the user equipment is operating in a state where the level of interference and noise is low, there can be no need for beam steering or at least for the generation of steering nulls to reduce interference. Similarly, where there are many different interferences from different directions, then the generation of steering nulls can not be particularly helpful. Thus, in example embodiments, the user equipment can determine at least one of the signal to interference plus noise ratio and the dominant interference ratio, DIR factor, before generating any particular radiation pattern and only if the signal to interference plus noise ratio is below a certain threshold and the DIR factor is above a certain threshold, indicating that there is one particular dominant interference, will the control circuitry associated with the antenna array generate a radiation beam pattern with a beam and at least one steering null. In this way, the processing capability associated with determining the preferred radiation pattern and applying the beamformed signal to the amplitude and / or phase shift circuitry is only used when the effect is particularly beneficial.

[0074] The criteria for whether to apply beam nulling are summarised as follows:

[0075] By evaluation of the DIR factor, it is determined whether there are valid conditions for applying the nulling technique. If the DIR factor is above a threshold and the SINR is below a threshold, then the beam nulling has good conditions for performance enhancement. If the DIR factor is below a certain threshold, then it would not make sense to perform beam nulling.

[0076] DIR factor definition

[0077] The dominant interference ratio indicates the ratio between the strongest interference and the rest of the interferences. It is defined as:

[0078]

[0079] where I1 represents the strongest interference. DIR can be interpreted as an indicator of the potential performance benefit obtained assuming ideal cancellation of the dominant interference.

[0080] Estimation of the DIR factor in 5G NR

[0081] By decoding the SSB (synchronisation signal block) burst, a high sampling rate and regular data source for estimating the surrounding cell power levels at the UE is available. From the SSB burst, the UE will be able to retrieve the signal strength of all target cells in range.

[0082] For this application, we propose to match the interference values with the signal strength of the target cells. The serving cell signal strength is not considered in the DIR factor evaluation.

[0083] In short, Ii will be assigned the RSRP (Reference Signal Received Power) value of the strongest target cell estimated from the SSB burst. Then, I2will be assigned the RSRP value of the second strongest target cell, and so on. Note that signal strength and interference level are not the same, however, we will compensate for this below.

[0084] When can a UE benefit from nulling interference?

[0085] Given the DIR factor computed as above, there are 2 elements to consider.

[0086] First, the UE checks if there is actual interference to cancel by evaluating the SINR level. Typical SINR can range from -10dB up to 30dB. A SINR_nulling_threshold is defined as the level at which nulling should be applied. This threshold is configurable and an example value can be 15dB.

[0087] Second, the estimated DIR factor should be compared to a DIR_nulling_threshold in order to determine if there is a dominant strong interference or several of similar strength. Nulling only occurs if there is a dominant strong interference.

[0088] In summary, the estimated DIR factor indicates the potential gain for nulling, while the SINR level indicates that there is data load on the strongest interference and that nulling is beneficial.

[0089] The logical Boolean expression for the decision criterion to apply beam nulling is thus:

[0090] ((SINR < SINR_nulling_threshold) & (DIR > DIR_nulling_threshold)).

[0091] Another potential issue that arises in antenna arrays within user equipment is that the radiation pattern around the user equipment can change depending on factors such as the proximity of any part of the user’s body or changes in the housing, for example, an additional protective cover mounted on the external housing of the UE, and / or the addition of a self-locking rod or other UE holder close to the antenna array, and / or operational changes of components within the user equipment, including activation or deactivation of components, and / or operational changes of components external to the user equipment, such as the insertion of a charger or data cable. These factors and thus the radiation pattern can change during the use of the user equipment when signals are being received. These factors can not impact the main beam excessively, but can have a significant impact on nulls in the radiation pattern. In fact, changes in conditions within or around the user equipment can cause changes in the standing wave at the user equipment, which in turn triggers changes in the radiation pattern, in particular changes in nulls.

[0092] Thus, in example embodiments in which the beamforming circuitry is forming a radiation pattern with one or more steered nulls, circuitry within the user equipment can monitor known conditions that affect the radiation pattern. This can be by directly detecting the conditions themselves (i.e. the switching on or off of components, the insertion of a charger) or by using proximity sensors to detect the proximity of a user or other device, and / or it can be by detecting changes in received power and / or signal to interference plus noise to detect changes in the radiation pattern.

[0093] When the circuitry determines such changes and when they exceed a certain threshold, then the beamforming circuitry can seek to change the beam steering signals applied to the amplitude and / or phase shift circuitry associated with the antenna array to compensate for the change in conditions at the user equipment and in particular, to compensate for changes in the steered nulls in order to seek to restore the radiation pattern to the same or at least similar to that before the change in conditions. In this way, changing beamforming signals associated with the antenna array can compensate for changing conditions within the user equipment that will affect the interference of the signal.

[0094] In some cases, changes in conditions that are expected to change the radiation pattern in a particular way can be detected and changes to the beam steering signals can be made without first monitoring the radiation pattern. This can allow the user equipment to react quickly to any changes and reduce processing power consumption. In this regard, machine learning can be used to determine how changes in various factors, such as the movement and / or proximity of a user, the removal of a cover or the opening or closing of a particular component, affect a particular steered null and the best way to compensate for these changes can be derived and stored. This learned behaviour can then be used to compensate for changes in conditions when they are detected without needing to first assess how signals and noise received at the user equipment are affected.

[0095] The beamforming signals or vectors applied to the amplitude and / or phase shift circuitry can be determined from a database which can include a limited pre-characterised set of combinations of phase shifts and / or power levels to be applied to different antenna element signals, which can be in the form of a codebook, storing signals for generating a beam in one direction and a null in another direction. Where the signals are to be adapted, an algorithm can be used to adapt them or, in some embodiments, another codebook can be used which sets different values to be applied in different environments.

[0096] Figure 1 A flowchart illustrating a method according to example embodiments is shown schematically. The scheme describes a UE beam phase shifter control state during CSI-RS (Channel State Information Reference Signal) UE beam tracking.

[0097] There are 6 states in common:

[0098] 1. Beam sweep

[0099] 2. Best beam only

[0100] 3. Apply best beam and null directions

[0101] 4. Null sweep

[0102] 5. Standing wave detection

[0103] 6. Standing wave compensation

[0104] State 1: Beam sweep state S1 is generally described as P3 phase of beam alignment.

[0105] The UE sweeps its set of possible beam directions to find the set of beam directions that gives the best downlink RSRP (Reference Signal Power). During this state, the UE can also determine the direction of the strongest interference by the SINR evaluated per beam.

[0106] Transition: At the end of the beam sweep, the UE will evaluate two conditions for transition states:

[0107] Condition: (DIR>thr) & (SINR<thr)

[0108] If true -> State 3

[0109] Else -> State 2.

[0110] After the best beam direction is determined, the UE will evaluate two conditions at comparator 50 to determine how to transition from this. These conditions are DIR (dominant interference ratio) and SINR (signal to interference plus noise ratio). Comparator 50 determines if the DIR is above a predetermined threshold and the SINR is below a certain threshold. If the DIR is above its threshold and the SINR is below its threshold, there is significant noise and dominant interference, so the method proceeds to S3 state 3 and forms beams and steers nulls, if not, the method proceeds to S2, state 2. State 2 applies only the best beam, and is selected if the signal to interference plus noise ratio is such that the signal is received at an acceptable level and / or there is no dominant interference, such that the provision of one or more steered nulls can not improve reception by any great amount, and therefore the overhead associated with providing these steered nulls can not be worth it.

[0111] State 2: “Best beam only” will direct the main beam of the UE towards the direction that maximizes the RSRP without steering any nulls.

[0112] Transition: Evaluate power drop, then DIR and SINR.

[0113] Condition: (RSRP < thrR),

[0114] If true -> State 1

[0115] If false -> Continue next expression

[0116] Condition: (DIR > thrD) & (SINR < thrS)

[0117] If true -> State 3

[0118] If false -> Stay in state

[0119] When operating in best beam only, if a power drop is detected, a transition can occur. This can be detected by the RSRP dropping below a certain threshold, and in this case the method can return from S2 to 1, i.e. state 1 and perform a beam sweep, whereas in case the power is above the threshold level, then DIR and SINR are evaluated again at a comparator 50, which can be an additional comparator or the same comparator as used when transitioning from state 1, and in case DIR is above the threshold and SINR is below the threshold, the UE transitions to S3, state 3, where beam and null steering is applied, whereas if it is false, it stays at S2 in state 2 with the best beam.

[0120] State 3: “Beam and null” will jointly direct the UE’s main beam towards the direction that maximizes the RSRP, while also directing the main null towards the direction of the strongest interference.

[0121] Transition: Evaluate power drop, then SINR, then DIR.

[0122] Condition: (RSRP < thrR),

[0123] If true -> State 1

[0124] If expression -> Continue next expression

[0125] Condition: (SINR > thrS)

[0126] If true -> Stay in state (then stay in state 3)

[0127] If false -> Continue next expression

[0128] Condition: (DIR > thrD)

[0129] If true -> State 4

[0130] If false -> State 2

[0131] If operating at S3 in state 3, there is a main beam directed towards the source and a main null steering beam directed towards the strongest interference. If there is a power drop and SINR and DIR pass certain thresholds, the state is transitioned. The condition of the power dropping below a certain threshold transitions the state back to SI, state 1 of beam sweeping. However, if the power does not drop below this threshold, but the signal to noise ratio is determined to be above a threshold at comparator 50, the UE stays at S3, in state 3, while if the power is below the threshold and DIR is above a certain threshold, the UE proceeds to S4, state 4, where a null scan is performed to detect an updated angular position of the steering null. As described below.

[0132] State 4: "Null scan" will perform a null scan while keeping the main beam fixed.

[0133] Transition: Evaluate power drop, then SINR, then DIR.

[0134] Condition: (RSRP < thrR),

[0135] If true -> state 1

[0136] If false -> continue next expression

[0137] Condition: (SINR > thrS)

[0138] If true -> stay in state (then stay in state 3)

[0139] If false -> continue next expression

[0140] Condition: (DIR > thrD)

[0141] If true -> state 5

[0142] If false -> state 2

[0143] At the end of the null scan S4, the received power is detected and if it is below a threshold, the UE returns to beam sweeping state 1 to redirect the beam. If the received power has not dropped significantly, then the SINR is determined and if it is determined to be above a threshold at comparator 50, the device returns to the beam and null direction of S3, state 3, while if it is below this threshold, the DIR is evaluated at comparator 50 and if it is above a DIR threshold, the device transitions to S5, state 5, where the standing wave associated with the UE is detected, while if there is no major interference, we return to state 2 where we only have the best beam.

[0144] State 5: "Standing wave detection", in which state the UE starts by triggering a state read of all standing wave determination units including external factors such as user interaction and use of a protective cover. It will then compare the latest state read on each unit with a previous read. If there is no change in state, it will transition to S3, State 3, otherwise it will transition to S6, State 6.

[0145] State 6: "Standing wave compensation", in which state the UE will apply the best front end settings for the new standing wave state, and then once applied it will change to S3, State 3.

[0146] In the figures, thrR, thrS, thrD are configurable thresholds associated with RSRP, SINR and DIR respectively.

[0147] State 5 is associated with determining whether the current radiation pattern, in particular the zero radiation pattern, has changed due to a change in conditions affecting the internal standing wave. Such a change can be detected with an internal standing wave detector such as shown in Figure 2 The standing wave detector can be part of a beam management entity including beam forming circuitry that determines and applies phase shifts and / or amplitude changes to signals to and from the antenna elements of the antenna array. The standing wave detector 24 includes a primary input parameter detection unit 26 and a secondary input parameter detection unit 28. The primary input detection unit 26 includes a proximity detector 27 for detecting proximity of a user, in particular a hand of a user, to the antenna array, and other detectors for detecting other factors affecting the radiation pattern such as whether there is a protective cover mounted on the user equipment. This can include a detector for detecting impedance changes of a sub-6 GHz antenna that can be adjacent to or share the same volume as the antenna array, which in this embodiment includes a mmWave panel.

[0148] There is also a second input parameter detection 28 which detects changes in components within the user equipment which can have an impact on the radiation pattern by generating their own standing waves. This can include detectors for detecting activation or power level changes and can include power management units (PMU), digital to analog converters (DAC), analog to digital converters (ADC), digital front end, self-interference cancellation, transmitter drivers / converter, power amplifiers for uplink (transmit) and low noise amplifiers for downlink (receive). Other electronic components which can affect standing waves include (but are not limited to) cameras, speakers, USB chargers and screens. These different elements are considered to be standing wave units and are configured to send a digital signal with information such as on / off or level indicators to the standing wave detector 24. Their current state is then compared to their previous state and if a change is detected then some compensation for the impact this can have on the radiation pattern is made, especially that the radiation nulls can start. This assessment can be made as necessary but proactively so as not to introduce excessive delay in the state change between state 4 and 5. Figure 1 The trigger for this assessment can vary but in some embodiments can be when the SINR falls below a SINR threshold required for the DIR factor assessment shown in Figure 1 State 5.

[0149] The background behind the standing wave compensation relates to the electrical ground plane associated with the antenna array which will generate standing waves which can not significantly affect the main beam shape but do significantly affect the side lobe shape and nulling properties of the array radiation pattern. In this regard the current generated by the antenna elements of the antenna array is required for radiation but ideally should be confined to the vicinity of the antenna array for a known and pre-characterized behavior. Large electrical ground planes (relative to the operating frequency of the antenna array and hence relative to the wavelength) will generate standing waves and while they do not significantly affect the main beam shape of the array under consideration they do significantly affect the side lobe shape and nulling properties of the array radiation pattern.

[0150] For each received CSI-RS sample in the PDSCH (Physical Downlink Shared Channel) of the UE implementing the embodiment, the RSRP and SINR values are estimated.

[0151] The factors affecting the radiation pattern or standing waves can be compensated in different ways which will be described later in relation to Figure 5 and Figure 6

[0152] ​The beam and steer nulls are generated by applying a beamforming vector to the amplitude and / or phase shift circuits associated with the different antenna elements of the antenna array. This vector can be generated in a number of ways, but in some embodiments it is selected from a database or codebook that stores such vectors. Figure 3 Such a database or codebook is shown schematically, storing vectors to be applied to the amplitude and / or phase shift circuits along with the associated beam and steer null directions. As can be seen, the first rows 60, 62 relate to nulls at around 30 0 degrees, with the main beam radiating in different directions. The next row 64 has a null shifted clockwise to around 60 0 degrees, and again has different directions for the main beam. Thus, after a beam sweep is performed by the UE to find the direction from which the signal is coming and the main interference direction has been identified, one of these patterns can be selected as preferred. The codebook entry corresponding to the identified beam and null direction is then selected and applied to the circuits that transmit or receive signals from the antenna elements of the antenna array.

[0153] Figure 4 The different conditions are shown schematically how they provide different standing waves and affect the radiation pattern, in particular the nulls. In these embodiments, line 70 corresponds to the UE in free space, while line 74 indicates the presence of a protective cover, and 72 indicates the case where the user touches a corner of the UE. The top left diagram is for an antenna array that is centered along the top edge of the UE (the shorter edge or side of the UE) and is configured to generate a -45 0 degree angular beam steering direction when looking towards the top of the UE. The top right diagram is a 2D cross section looking from the front of the device. The lower diagrams are examples of the effect of the standing wave for the antenna array, which is designed with a 10mm offset (from the center of the shorter side of the UE) and is configured to generate a -30 0 degree angular beam steering direction, where the left hand diagram is a 2D cross section looking from the top of the device, and the right hand diagram is a 2D cross section looking from the front of the device. As can be seen in both examples, the main beam is preserved, but the variation in the nulls can be as high as 15 to 20 dB in some directions, and 5 to 10 dB in many directions. In summary, the beam nulls are sensitive to the standing wave, and mitigation of this effect will help to maintain an effective SINR in a dynamic UE environment.

[0154] In some example embodiments, the UE may alternatively have sides (or edges) of equal length, and thus the antenna array may be designed to be located at the center of such a side of the UE, at an offset from the center of such a side of the UE, or near the end of such a side of the UE. It should be understood that the location of the antenna element array may include wrapping around one or more corners and / or one or more sides of the UE, such that the antenna array may have one or more antenna elements on one side of the UE and one or more antenna elements on the other side of the UE to form one of the antenna arrays. The sides or edges of the UE are described as any one of four sides, where each side forms a secondary surface of the UE, and where there are also two additional faces to form the primary surface of the UE, such that the four sides and two faces together form the enclosure or housing of the UE. In some example embodiments, the UE may include a single housing for all its electronic components and antennas, and in some embodiments, the UE may include two or more housings joined together using mechanical components, and where some or all of the electronic components and / or antennas may be distributed across two or more housings, and / or some or all of the electronic components and / or antennas may be located in only one of the two or more housings.

[0155] Figure 5 The diagram illustrates how the interference level at the UE is affected by the presence of a standing wave (SWR) manipulating the null. The left-hand plot shows the low signal in the direction of the main interference prior to the SWR, while the right-hand plot shows how the interference signal increases with the influence of the null.

[0156] Figure 6 A dedicated lookup table is shown that matches a codebook entry for a given interference angle with an electronic component that has been identified as having triggered a standing wave, and provides adjustments to that codebook entry. These adjustments compensate for changes in the radiation pattern caused by the detected standing wave. Changes in the radiation pattern caused by standing waves can be determined in various ways, and... Figure 6 In the example, it is known that components within the UE that affect the standing wave are associated with different adjustment entries so that when a component switches between on and off states, the corresponding compensation for the beamforming signal vector can be selected from a lookup table.

[0157] One advantage of this method is its speed and lack of training requirements. By pre-compiling / estimating this relationship, the UE nulling mechanism can compensate for predicted standing waves triggered by changes in this component, thus improving the codebook selection used for standing wave compensation. Different granularities can be considered; however, typically only a few elements within the standing wave unit will have a significant impact, and this allows the number of entries to be reduced and customized to suit these specific elements.

[0158] Another method to compensate for the change in radiation pattern caused by the standing wave is a system cyclic search of all codebook entries corresponding to the detected signal and interference directions. Once a codebook entry triggers the SINR to be increased above the threshold for selecting that entry. This method can not be particularly fast.

[0159] An alternative is the closest codebook entry search, where the nearby codebook entries are searched first, and this is Figure 7 schematically illustrated in Figure 7 It is shown how the best codebook entry can be one close to the current codebook entry. Therefore, the likelihood of a nearby codebook entry improving performance is higher than the likelihood of a distant codebook entry. Therefore, the use of nearby codebook entries first improves the probability of finding an improved codebook entry after improving the standing wave interference, and therefore, the system will likely find an improved radiation pattern faster.

[0160] The closest codebook entry search will start from the codebook entry used before entering Figure 2 "state 5" in Figure 8 is called the "initial codebook index". Then, the search will start estimating the relative interference gain at the closest codebook entry by alternating the following operations: first incrementing the codebook index, then decrementing the codebook index. For each alternation, the step size is increased by 1 sample. Once the desired performance is reached, the search is stopped. This is parameterized by a manufacturer configurable SINR threshold. This closest codebook entry search is still not as fast as the "pre-characterized link" method.

[0161] Figure 9 A UE 5 according to an embodiment is shown. The UE 5 comprises a millimeter wave antenna array 10 comprising a plurality of antenna elements 12. The antenna array 10 is connected to a beam management entity 20, which comprises amplitude and phase shift circuitry 22, which controls the phase and amplitude of RF signals applied to or received from the antenna elements, which in turn set the direction and amplitude of the radiation beam(s) from the array, so that signals to or from the source are amplified, and signals to and from the interference are reduced. In effect, a beam direction and at least one steered null direction are provided. Once the main beam is selected and directed to the base station (network node), the UE communicates with the BS, i.e. the UE receives RF signals from the BS and transmits RF signals to the BS.

[0162] The UE 5 also includes control circuitry 40 configured to determine the signal strength of the interfering signals received at the antenna array and from this determine the DIR. Within the circuitry 40 there is also a comparator for comparing the DIR with a predetermined threshold. The circuitry 40 is also configured to determine the SINR and compare this with a threshold and to determine the RSRP. In this way the control circuitry 40 is able to determine when the DIR is above a threshold and the SINR is below a threshold and at this time to send a control signal to the beam management entity 20 indicating that a controlled beam with at least one steered null is required. The directions of these beams can be determined by a conventional beam sweeping procedure and then the required beam forming signal vectors are selected from the database 30. These are then applied to the amplitude and / or phase shift circuitry 22.

[0163] The beam management entity 20 also includes a standing wave detector unit similar to that shown in Figure 2 In the event that a change in the radiation pattern is detected by detecting a standing wave from the standing wave detector or by detecting a change in the received power, a change in the SINR and / or DIR, then the circuitry 40 will seek to compensate for the change(s) in the steered nulls by varying the beam forming signals applied to the amplitude and / or phase circuitry 22. This can be done by selecting updated entries from the database 30 or by selecting adjustment values from a look-up table such as that shown in Figure 5

[0164] In summary, the embodiments provide a unique UE receiver and method which enables increased high performance SINR via beam nulling and in some embodiments implements standing wave compensation.

[0165] Desired and undesired signals can be tracked simultaneously while applying a UE antenna radiation pattern that improves the signal to interference and noise ratio. Since the electrical dimensions of the UE chassis, legacy antennas (e.g. cellular and non-cellular antenna elements for any radio system other than 5G), and electrically active components such as RF elements, cameras, speakers, and sensors near the antenna array on the phone are large, the activated and pattern optimized UE antenna array will experience standing waves. The standing waves affect the depth and / or direction of the nulls as they are affected by small changes in the near field signal. These standing waves can be detected and compensated for by adjusting the nulls to maintain a good signal to interference and noise ratio.

[0166] ​The throughput and data decoding performance of a UE such as a 5G NR mmWave terminal using the proposed procedure will be improved compared to a phone not using this technique under interference conditions. While the embodiments are particularly effective when applied to 5G NR mmWave terminals, the embodiments are not limited to this, but can be applied to other user equipment using any radio protocol that requires the use of antenna arrays.

[0167] The steps of the present procedure can include:

[0168] a. Novel antenna pattern control and standing wave compensation scheme including user and cover detection

[0169] b. Novel beam nulling application criteria

[0170] c. Novel standing wave change detection

[0171] d. Novel standing wave compensation method for beam nulling

[0172] In fact, the problem of how to simultaneously track the desired signal and the undesired signal(s) is solved, while applying a UE antenna array radiation pattern that improves the signal to interference and noise ratio, and enabling the UE to compensate for the dynamic effects of the standing wave in order to keep the null steering effective.

[0173] Performing beam nulling without these elements will result in poor performance.

[0174] The embodiments seek to determine whether there are valid conditions for applying the nulling technique by evaluating the dominant interference ratio (DIR) factor and the SINR level. If the DIR factor is above a threshold and the SINR is below a threshold, the beam nulling has good performance enhancement conditions. If the DIR factor is below a certain threshold, then it would be pointless to perform beam nulling. If the SINR is very good, there is no interference to further cancel.

[0175] Detecting standing wave changes

[0176] The UE will monitor key electrical feed components that can be standing wave change contributors. When these electronic components change state (e.g. from on to off, and vice versa), the UE will use them as a gate for starting compensation and adjust its nulling for the new standing wave conditions and maintain high performance interference nulling.

[0177] A novel standing wave compensation method for beam nulling is provided, in which a pre-characterized table of the relationship between the best codebook and the active elements that affect the standing wave is proposed.

[0178] The UE can be any portable electronic device with wireless communication capabilities such as, but not limited to, a portable electronic device, a smart phone, a mobile phone, a robot, an IoT device, a transportable electronic device (a radio in a car, an airplane, a ship, a vehicle, etc.), a smart watch, a portable computer, a laptop computer, a tablet computer, a portable music player, a portable video device, a portable navigation device, a wearable electronic device with wireless communication capabilities.

[0179] Those skilled in the art will readily recognize that steps of various above-described methods can be performed by programmed computers. Herein, some embodiments are also intended to cover program storage devices, e.g., digital data storage media, which are machine or computer readable and encode machine-executable or computer-executable programs of instructions, wherein said instructions perform some or all of the steps of some above-described methods. The program storage devices can be, e.g., digital memories, magnetic storage media such as magnetic disks and magnetic tapes, hard disk drives, or optically readable digital data storage media. The embodiments are also intended to cover computers programmed to perform said steps of some above-described methods.

[0180] While embodiments of the application have been described in the foregoing paragraphs in reference to various examples, it will be understood that modifications can be made to the examples given without departing from the scope of the application as claimed.

[0181] Features described in the preceding description can be used in combinations other than the combinations explicitly described.

[0182] Although functions have been described with reference to certain features, those functions can be performed by other features whether or not the other features are described.

[0183] Although features have been described with reference to certain embodiments, those features can also be present in other embodiments whether or not the other embodiments are described.

[0184] While efforts have been made to account for prior art, it should be understood that various modifications can be made to the embodiments described in this specification without departing from the spirit or scope of the application as claimed.

Claims

1. An apparatus for communication, comprising: a beamformed signal generator configured to generate a beamformed signal for application to at least one of amplitude and phase shift circuits associated with an antenna array for providing a radiation pattern; and a determining component configured to determine a signal strength of an interfering signal received at the antenna array within a user equipment, to determine a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals, and to determine a signal to interference plus noise ratio; and a comparator configured to compare the dominant interference ratio to a predetermined ratio value and to compare the signal to interference plus noise ratio to a threshold value, and to generate a control signal for controlling the beamformed signal generator to generate a radiation pattern comprising a beam and at least one steered null in case the dominant interference ratio exceeds the predetermined ratio value and the signal to interference plus noise ratio exceeds the threshold value.

2. The apparatus of claim 1, wherein: the comparator is further configured to generate a control signal for controlling the beamformed signal generator to generate a radiation pattern comprising a beam and no steered null in response to the dominant interference ratio being less than the predetermined ratio value.

3. The apparatus of claim 1, the determining component is further configured to generate a control signal for controlling the beamformed signal generator to generate a radiation pattern comprising a beam and no steered null in response to the signal to interference plus noise ratio being greater than a predetermined value.

4. The apparatus of claim 1, further comprising: a monitoring component configured to monitor at least one condition change affecting a null in a radiation pattern at the user equipment when the beamformed signal applied to the at least one of the amplitude and phase shift circuits comprises a beamformed signal generating a radiation pattern comprising a beam and at least one steered null at the user equipment; the monitoring component is configured to generate a control signal to apply to the beamformed signal generator to control the beamformed signal generator to modify the beamformed signal to at least partially compensate for the change of the at least one steered null in the radiation pattern in response to detecting the at least one condition change.

5. The apparatus of claim 4, the beamformed signal generator is configured to modify the beamformed signal to generate a plurality of updated radiation patterns by a plurality of changes of an angular position of the at least one steered null; the determining component is configured to determine a preferred angular position of the at least one steered null by determining a received power, a signal to interference plus noise ratio and the dominant interference ratio for the plurality of updated radiation patterns.

6. The apparatus of claim 4, wherein the monitoring component is configured to detect the at least one condition change from at least one of: a decrease in a received power detected at the antenna array; a decrease in a signal to interference plus noise ratio; and an increase in the dominant interference ratio.

7. The apparatus of claim 4, wherein the monitoring component is configured to detect the at least one condition change by detecting at least one of a change in user proximity from a proximity sensor, and a change in an operating condition of at least one predetermined component of a plurality of predetermined components within the user device.

8. The apparatus of claim 4, further comprising a database for storing a plurality of signal vectors for application to at least one of the amplitude and phase shift circuits to generate different radiation patterns; the beamforming signal generator is configured to generate the beamforming signal by selecting one of the plurality of signal vectors.

9. The apparatus of claim 8, wherein the beamforming signal generator is configured to modify the beamforming signal to at least partially compensate for a change in the at least one steered null in the radiation pattern by selecting an updated value from the database and determining from the determining component whether the signal-to-interference-plus-noise ratio is increased and whether to not discard the selected value and select a further value.

10. The apparatus of claim 8, wherein the beamforming signal generator is configured to modify the beamforming signal by selecting a modified database entry related to a detected predetermined operating change.

11. The apparatus of claim 6, wherein the beamforming signal generator is configured to modify the beamforming signal to at least partially compensate for a change in the at least one steered null in the radiation pattern by applying an algorithm related to a determined operating condition change to the beamforming signal and determining from the determining component whether the signal-to-interference-plus-noise ratio is increased.

12. The apparatus of any one of claims 4 to 11, wherein the monitoring component, determining component, beamforming signal generator, and comparator comprise: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the following operations: determine a signal strength of an interfering signal received at an antenna system within a user device; determine a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; and compare the dominant interference ratio to a predetermined ratio value; and generate a beamforming signal for application to at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and at least one steered null in the event that the dominant interference ratio exceeds the predetermined ratio value.

13. A user device comprising: an antenna array comprising a plurality of antenna elements; at least one of amplitude and phase shift circuits associated with the antenna elements of the antenna array; and the apparatus of any one of the preceding claims.

14. A method for communication comprising: determining a signal strength of an interfering signal received at an antenna array within a user device; determining a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; determining a signal to interference plus noise ratio; and comparing the dominant interference ratio to a predetermined ratio value; comparing the signal to interference plus noise ratio to a threshold value; and generating a beamforming signal for application to at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and at least one steered null, in the event that the dominant interference ratio exceeds the predetermined ratio value and the signal to interference plus noise ratio exceeds the threshold value.

15. A computer program product comprising a computer program which, when executed by a processor of an apparatus, causes the apparatus to: determine signal strengths of interfering signals received at an antenna array within a user equipment; determine a dominant interference ratio indicative of a strength of a strongest interfering signal relative to strengths of other interfering signals; determine a signal to interference plus noise ratio; and compare the dominant interference ratio to a predetermined ratio value; compare the signal to interference plus noise ratio to a threshold value; and generate a beamforming signal for application to at least one of amplitude and phase shift circuits associated with the antenna array to generate a radiation pattern comprising a beam and at least one steered null, in the event that the dominant interference ratio exceeds the predetermined ratio value and the signal to interference plus noise ratio exceeds the threshold value.

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