Patent Description:
For example, transmission schemes and reception schemes based on the use of narrow beams might be needed at high frequencies to compensate for propagation losses. For a given communication link, a beam can be applied at both the network side (such as at the transmission and reception point (TRP) of a network node) and the user side (such as at terminal devices served by the network node). A beam pair link (BPL) is defined by the beam used by the TRP (denoted TRP beam) for communicating with the terminal device and the beam used by the terminal device (denoted TD beam) for communicating with the TRP. Each of the TRP beam and the TD beam could be used for any of transmission and reception. Likewise, there could be separate BPLs for downlink communications (where the TRP beam is a transmission (TX) beam and where the TD beam is a reception (RX) beam) and uplink communications (where the TRP beam is an RX beam and where the TD beam is a TX beam).

In general terms, a beam management procedure is used to discover and maintain BPLs. A BPL is expected to be discovered and monitored by the network using measurements on downlink reference signals used for beam management, such as channel state information reference signals (CSI-RS). The CSI-RS for beam management can be transmitted periodically, semi-persistently or aperiodic (such as being event triggered) and they can be either shared between multiple terminal devices or be device-specific.

In order to find a suitable TRP beam the TRP transmits CSI-RS in different TRP TX beams on which the terminal devices performs reference signal received power (RSRP) measurements and reports back the N best TRP TX beams (where the value of N can be configured by the network). Furthermore, the CSI-RS transmission on a given TRP TX beam can be repeated to allow the terminal device to evaluate suitable TD beams, thus enabling so-called TD RX beam training.

The terminal devices and/or the TRP of the network node could implement beamforming by means of analog beamforming, digital beamforming, or hybrid beamforming. Each implementation has its advantages and disadvantages. A digital beamforming implementation is the most flexible implementation of the three but also the costliest due to the large number of required radio chains and baseband chains. An analog beamforming implementation is the least flexible but cheaper to manufacture due to a reduced number of radio chains and baseband chains compared to the digital beamforming implementation. A hybrid beamforming implementation is a compromise between the analog and the digital beamforming implementations. As the skilled person understands, depending on cost and performance requirements of different terminal devices, different implementations will be needed.

<CIT> relates to a method for beam selection in a radio transceiver device. According to one aspect, a set of transmit beams are defined that simultaneously provides for space division multiplexing, multiple-input multiple output (MIMO transmission and opportunistic beamforming. Further, the addition of a wide beam guarantees a minimum acceptable performance for all user devices.

During beam pair establishment (e.g. using the example of TD RX beam training for a terminal device with an analog antenna array), it is expected that the terminal device scans through narrow pencil beams pointing in different directions and then selects the TD RX beam that gives the highest measured RSRP. One reason for using narrow beams is that the narrower the beams, the higher the antenna gain. Such narrow high gain beams are especially useful in line of sight channels where the angular spread in the channel seen by the terminal device is rather small. However, there could be situations when it is more beneficial to use a broad beam, and it could hence be difficult for the terminal device to select which beam to use.

Hence, there is still a need for an improved beam selection procedure.

An object of embodiments herein is to provide an efficient beam selection procedure.

According to a first aspect there is presented a terminal device according to claim <NUM>.

According to a second aspect there is presented a method according to claim <NUM>.

According to a third aspect there is presented a computer program according to claim <NUM>.

Advantageously these aspects provide efficient beam selection that can be used to streamline, or make more effective, a traditional beam selection procedure.

Advantageously these aspects result in selection of a beam that could be used to establish a robust communication link, without resulting in any significant drop in received power.

<FIG> is a schematic diagram illustrating a communications network <NUM> where embodiments presented herein can be applied. The communications network <NUM> could be a third generation (<NUM>) telecommunications network, a fourth generation (<NUM>) telecommunications network, or a fifth (<NUM>) telecommunications network and support any 3GPP telecommunications standard.

The communications network <NUM> comprises at least one network node <NUM> configured to, via radio transceiver device <NUM>, provide network access to radio transceiver device <NUM> in a radio access network <NUM>. In some embodiments radio transceiver device <NUM> is part of, integrated with, or collocated with, a terminal device and radio transceiver device <NUM> is part of, integrated with, or collocated with, a radio access network node or a TRP. Further, in some embodiments radio transceiver device <NUM> is part of, integrated with, or collocated with the network node <NUM>.

The radio access network <NUM> is operatively connected to a core network <NUM>. The core network <NUM> is in turn operatively connected to a service network <NUM>, such as the Internet. Radio transceiver device <NUM> is thereby, via the network node <NUM> and radio transceiver device <NUM>, enabled to access services of, and exchange data with, the service network <NUM>.

Examples of network nodes are radio access network nodes, radio base stations, base transceiver stations, Node Bs, evolved Node Bs, gigabit Node Bs, access points, and access nodes. Examples of terminal devices are wireless devices, mobile stations, mobile phones, handsets, wireless local loop phones, user equipment (UE), smartphones, laptop computers, tablet computers, network equipped sensors, network equipped vehicles, and so-called Internet of Things devices.

Radio transceiver device <NUM> and radio transceiver device <NUM> are assumed to be configured to use beam forming when communicating with each other. In <FIG> this is illustrated by beams, collectively identified at reference numeral <NUM> for beams being used at radio transceiver device <NUM>, and individually identified at reference numerals 150a, 150b, 150c, 150d,. , <NUM>, 160a, 160b for beams being used at radio transceiver device <NUM>. The beams could be used for either transmission only, or reception only, or for both transmission and reception.

Radio transceiver device <NUM> will below be denoted a first radio transceiver device and radio transceiver device <NUM> will below denoted a second radio transceiver device. However this is for notational purposes only with the purpose of simplifying the description of the herein disclosed embodiments and does not imply any hierarchical relation between radio transceiver device <NUM> and radio transceiver device <NUM>.

As disclosed above it could be difficult for radio transceiver devices, such as terminal devices but also radio access network nodes, to select which beam to use. In further detail, selecting the best narrow beam (i.e. "best" according to some quality criterion, such as link quality of the narrow beam) might not be optimal in scenarios where narrow beams suffer from poor robustness characteristics. A wide beam is typically more robust against movement, rotation and blocking, of any of the radio transceiver devices, but may offer a weaker link (i.e. "weak" according to some quality criterion, such as link quality of the link resulting from using the corresponding narrow beam) due to lower beamforming gain.

The embodiments disclosed herein thus relate to mechanisms for beam selection and configuring a first radio transceiver device <NUM> for such beam selection. In order to obtain such mechanisms there is provided a first radio transceiver device <NUM>, a method performed by the first radio transceiver device <NUM>, a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the first radio transceiver device <NUM>, causes the first radio transceiver device <NUM> to perform the method. In order to obtain such mechanisms there is further provided a network node <NUM>, a method performed by the network node <NUM>, and a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the network node <NUM>, causes the network node <NUM> to perform the method.

<FIG> are flowcharts illustrating embodiments of methods for beam selection as performed by the first radio transceiver device <NUM>. <FIG> is a flowchart illustrating an embodiment of a method for configuring a first radio transceiver device <NUM> for beam selection as performed by the network node <NUM>. The methods are advantageously provided as computer programs 1020a, 1020b.

Reference is now made to <FIG> illustrating a method for beam selection as performed by the first radio transceiver device <NUM> according to an embodiment.

When, for example, performing beam training, the first radio transceiver device <NUM> could include one wide beam in the set of beams to be evaluated. As will be disclosed below, the set of beams to be evaluated could be generated by either the first radio transceiver device <NUM> or the second radio transceiver device <NUM> and be used for either reception or transmission. Particularly, the first radio transceiver device <NUM> is configured to perform step S102:
S102: The first radio transceiver device <NUM> obtains link quality estimates of a radio signal conveyed to the first radio transceiver device <NUM> from a second radio transceiver device <NUM> by means of at least a first beam 150a-<NUM> taken from a first beam set and a second beam 160a, 160b. The second beam 160a, 160b is wider than the first beam 150a-<NUM>.

It is assumed that at least for some scenarios a narrow beam has higher link quality than a wide beam (at least in such scenarios where there is line of sight between transmitter and receiver and the narrow beam is pointing in the line of sight direction) and hence that the link quality estimate of the first beam is higher than the link quality estimate of the second beam. But on the other hand it is assumed that the wide beam is more robust than the narrow beam. Robustness can here be defined in terms of blocking, movement of the first radio transceiver device <NUM>, etc. Robustness will hereinafter be represented by a compensation factor as applied to the link quality estimates of the second beam. Then, instead of selecting the beam strictly based on highest link quality, the first radio transceiver device <NUM> makes the decision as a trade-off between the narrow beam and the wide beam by jointly considering the link quality and robustness. Particularly, the first radio transceiver device <NUM> is configured to perform step S104:
S104: The first radio transceiver device <NUM> selects which one of the first beam 150a-<NUM> and the second beam 160a, 160b to use for continued communications of radio signals with the second radio transceiver device <NUM>. The beam is selected in accordance with a comparison between the link quality estimates of the first beam 150a-<NUM> and compensated link quality estimates of the second beam 160a, 160b.

This allows a wide beam to be selected although it has worse link quality than a narrow beam, thereby balancing link quality and robustness.

Embodiments relating to further details of beam selection as performed by the radio transceiver device <NUM> will now be disclosed.

There may be different ways to select the first beam from the first beam set. In some aspects link quality estimates of the radio signal are obtained for several beams in the first beam set and the first beam has best link quality estimate of all the beams for which the link quality estimates are obtained. That is, according to an embodiment the first beam 150a-<NUM> has best link quality estimates of all beams 150a-<NUM>, 160a, 160b in which the radio signal is received.

There may be different ways to select the beams 150a-<NUM> in the first beam set. It could be that there is only one single beam in the first beam set. In other aspects the first beam set comprises narrow pencil beams with different pointing directions. Particularly, according to an embodiment the first beam set comprises at least two beams 150a-<NUM> of same width but with mutually different pointing directions. The second beam 160a, 160b is wider than all beams 150a-<NUM> of the first beam set.

There may be different ways to select the second beam. In some aspects there is a single second beam. In other aspects the second beam is taken from a second beam set. That is, according to an embodiment the second beam 160a, 160b is taken from a second beam set, and all beams 160a, 160b of the second beam set are wider than the first beam 150a-<NUM>.

Further aspects of the first beam, the first beam set, the second beam, and the second beam set will be disclosed below.

The beams could belong to either the first radio transceiver device <NUM> or the second radio transceiver device <NUM>.

That is, according to a first aspect the beams belong to the first radio transceiver device <NUM> and are hence used for reception of the radio signal. That is, according to an embodiment the radio signal is conveyed by being received by the first radio transceiver device <NUM> in at least the first beam 150a-<NUM> and the second beam 160a, 160b.

Further, according to a second aspect the beams belong to the second radio transceiver device <NUM> and are hence used for transmission of the radio signal. That is, according to an embodiment the radio signal is conveyed by being transmitted by the second radio transceiver device <NUM> in at least the first beam 150a-<NUM> and the second beam 160a, 160b.

Thus, although the inventive concept as herein disclosed is mainly described as representing a TD RX beam selection in the downlink, the inventive concept is equally applicable for TRP TX beam selection in the downlink, or to TD TX beam selection in the uplink or TRP RX beam selection in the uplink.

There could be different ways to define the compensated link quality estimates. In some aspects the compensated link quality estimates are defined by means of a compensation value. Particularly, the compensated link quality estimates of the second beam 160a, 160b are defined as the link quality estimates of the second beam 160a, 160b increased with a compensation value. A compensation value could thus be used during the beam selection, where the compensation value represents an acceptable drop in link quality between the best narrow beam (as defined by the first beam) and the wide beam (as defined by the second beam).

With intermediate reference again to <FIG>, assume that the network node <NUM> has configured the first radio transceiver device <NUM> with an TD RX beam training procedure where the first radio transceiver device <NUM> is allowed to evaluate five TD RX beams, and hence the network node <NUM> transmits, via the second radio transceiver device <NUM>, five reference signals in the same TRP TX beam. The first radio transceiver device <NUM> determines to evaluate four narrow beams (beams 150a, 150b, 150c, 150d, hereinafter denoted B1, B2, B3, B4) and one wide beam (beam 160a, hereinafter denoted B5). Assume that the RSRP for the TD RX beams became: B1 = -100dBm, B2 = -95dBm, B3 = -110dBm, B4 = - 120dBm, and B5 = -97dBm.

If the acceptable degradation is, say, x dB, where x><NUM> and x thus defines the compensation value, then if the RSRP of the wide TD RX beam is less than x dB worse than the RSRP best narrow TD RX beam, the first radio transceiver device <NUM> selects the wide TD RX beam. Assume further that the compensation value for the wide beam is 3dB, which thus means that if the wide beam has less than 3dB lower RSRP compared to the best narrow beam, the first radio transceiver device <NUM> should select the wide beam. In the present illustrative example the best beam, B2, has only <NUM> dB higher RSRP compared to the wide beam, and hence the first radio transceiver device <NUM> will select to use the wide beam, B5.

There could be different ways to determine the compensation value.

In some aspects the compensation value takes into account how the first radio transceiver device <NUM> is moving. According to an embodiment the compensation value depends on at least one of: current speed, current rotation rate, and previous blocking statistics of the first radio transceiver device <NUM>. Typically, the higher speed the first radio transceiver device <NUM> has, the quicker the first radio transceiver device <NUM> rotates, and/or the higher the risk of the first radio transceiver device <NUM> experiencing blocking, the larger the wide beam compensation value could be. The compensation value could thus be adaptively set such that a larger link quality loss is accepted for high expected variation of the selected beam coverage area anticipated cost of losing the beam link.

In some aspects the compensation value takes into account how much worse the link quality of another narrow beam is. Particularly, according to an embodiment the compensation value is dependent on link quality estimates of the radio signal as received in a second first beam 150a-<NUM> taken from the first beam set.

In some aspects the so-called another narrow beam is neighbouring the best narrow beam. That is, according to an embodiment the first beam 150a-<NUM> and the second first beam 150a-<NUM> are neighbouring beams in beam space.

In some aspects the so-called another narrow beam is the second best narrow beam. That is, according to an embodiment the second first beam 150a-<NUM> has worse link quality estimates than only the first beam 150a-<NUM>.

In case any neighboring narrow beams have almost the same link quality as the best narrow beam, the radio propagation channel will be rather robust with respect to rotation of the first radio transceiver device <NUM>, and hence a low compensation value can be used.

In some aspects each wide beam has its own compensation value. There could thus be more than two different beam widths (e.g. the standard narrow beams plus medium-width plus wide), with different degradation compensation values. That is, according to an embodiment the second beam set comprises beams 160a, 160b of at least two different widths, each width of which being associated with a respective compensation value for compensating the link quality estimates.

There could be different occasions in which the link quality estimates are obtained, such as during regular data transmission or during dedicated beam training. Thus, according to an embodiment the link quality estimates are obtained during a beam training procedure of the first radio transceiver device <NUM>.

There could be different examples of link quality estimates. For example, the link quality estimates could be obtained in terms of reference signal received power (RSRP), or signal to interference ratio (SIR), or signal to interference plus noise ratio (SINR).

There could be different examples of signals for which the link quality estimates are obtained. In some aspects the estimate are obtained from measurements of reference signals in the radio signal. Particularly, the radio signal could comprise reference signals, such as uplink sounding reference signals (SRS) or downlink channel state information reference signals (CSI-RS), and the link quality estimates could then be obtained for the reference signals.

There could be different ways for the first radio transceiver device <NUM> to know how to perform the selection in step S104. Either it is hard-coded in the first radio transceiver device <NUM> how to select the beam to use, or the first radio transceiver device <NUM> is configured by another device how to select the beam to use. Particularly, according to an embodiment, how to select which one of the first beam 150a-<NUM> and the second beam 160a, 160b to use for continued communications of radio signals with the second radio transceiver device <NUM> is configured by network information. The network information could be obtained by the first radio transceiver device <NUM> from the network node <NUM>.

There could be different ways for the beams to be generated. In some aspects the beams are generated using phase shifts only. Particularly, according to an embodiment the at least first beam 150a-<NUM> and the second beam 160a, 160b are created by beamforming of antenna elements of an antenna array where the beamforming consists only of applying phase shifts to the antenna elements. In other aspects the beams are generated using a combination of amplitude tapering and phase shifts. Particularly, according to another embodiment the at least first beam 150a-<NUM> and the second beam 160a, 160b are created by beamforming of antenna elements of an antenna array where the beamforming comprises applying a combination of phase shifts and amplitude tapering to the antenna elements. Wide beams as well as narrow beams could thus be generated by only varying the phase settings of an analog antenna array, or by varying both phase settings and amplitude settings of an analog antenna array. In case the analog array is dual-polarized, so-called dual-polarized beamforming, as further described in <CIT> and <CIT>, can be used to create the beams. However, the inventive concept could be applied irrespective of the underlying beamforming hardware structure. Thus, while the present embodiment describes the use of analog beamforming, the inventive concept is equally applicable to digital beamforming, in which case the network node <NUM> would, via the second radio transceiver device <NUM>, transmit a single CSI-RS in the radio signal, and where the different beam options are evaluated by the first radio transceiver device <NUM> estimating the CSI-RS in the received radio signal.

Reference is now made to <FIG> illustrating methods for beam selection as performed by the radio transceiver device <NUM> according to further embodiments. It is assumed that steps S102, S104 are performed as described above with reference to <FIG> and a thus repeated description thereof is therefore omitted.

In view of what has been disclosed above, a wide beam (as defined by the second beam) is selected if its performance is not significantly worse (as defined by the compensation value) than the performance of the narrow beam (as defined by the first beam). Particularly, according to an embodiment the first radio transceiver device <NUM> is configured to perform step S104a as part of the selecting in step S104:
S 104a: The first radio transceiver device <NUM> selects to use the second beam 160a, 160b for continued communications of radio signals with the second radio transceiver device <NUM> only when the link quality estimates of the second beam 160a, 160b are within the compensation value of the link quality estimates of the first beam 150a-<NUM>.

That is, the second beam 160a, 160b is selected when the link quality estimates of the second beam 160a, 160b as compensated by the compensation value are not worse than the link quality estimates of the first beam 150a-<NUM>.

Otherwise the narrow beam (as defined by the first beam) is selected. Particularly, according to an embodiment the first radio transceiver device <NUM> is configured to perform step S104b as part of the selecting in step S104:
S 104b: The first radio transceiver device <NUM> selects to use the first beam 150a-<NUM> for continued communications of radio signals with the second radio transceiver device <NUM> when the link quality estimates of the second beam 160a, 160b are not within the compensation value of the link quality estimates of the first beam 150a-<NUM>).

That is, the first beam 150a-<NUM> is selected when the link quality estimates of the second beam 160a, 160b as compensated by the compensation value are still worse than the link quality estimates of the first beam 150a-<NUM>.

Once the beam has been selected it can be used during communications between the first radio transceiver device <NUM> and the second radio transceiver device <NUM>. Particularly, according to an embodiment the first radio transceiver device <NUM> is configured to perform step S106:
S106: The first radio transceiver device <NUM> communicates with the second radio transceiver device <NUM> using the selected beam. In view of what has been disclosed above the selected beam could belong to either the first radio transceiver device <NUM> or the second radio transceiver device <NUM>.

Reference is now made to <FIG> illustrating a method for configuring a radio transceiver device <NUM> for beam selection as performed by the network node <NUM> according to an embodiment.

As disclosed above, the first radio transceiver device <NUM> is configured to obtain link quality estimates of a radio signal conveyed to the first radio transceiver device <NUM> from a second radio transceiver device <NUM> by means of at least a first beam 150a-<NUM> taken from a first beam set and a second beam 160a, 160b. The second beam 160a, 160b is wider than the first beam 150a-<NUM>.

In some aspects it is the network node <NUM> that configures the first radio transceiver device <NUM> how to select which beam to use. Thus, the network node <NUM> is configured to perform step S202:
S202: The network node <NUM> configures the first radio transceiver device <NUM> to select to use, for continued communications of radio signals with the second radio transceiver device <NUM>, one of the first beam 150a-<NUM> and the second beam 160a, 160b. The beam is selected in accordance with a comparison between the link quality estimates of the first beam 150a-<NUM> and compensated link quality estimates of the second beam 160a, 160b.

Embodiments relating to further details of configuring a radio transceiver device <NUM> for beam selection as performed by the network node <NUM> will now be disclosed.

In general terms, embodiments disclosed above with reference to methods performed by the first radio transceiver device <NUM> are equally applicable to the network node <NUM>.

Thus, with reference to what has been disclosed above, according to an embodiment the radio signal is conveyed by being received by the first radio transceiver device <NUM> in at least the first beam 150a-<NUM> and the second beam 160a, 160b.

Thus, with further reference to what has been disclosed above, according to an embodiment the radio signal is conveyed by being transmitted by the second radio transceiver device <NUM> in at least the first beam 150a-<NUM> and the second beam 160a, 160b.

Thus, with further reference to what has been disclosed above, the compensated link quality estimates of the second beam 160a, 160b are defined as the link quality estimates of the second beam 160a, 160b increased with a compensation value.

Thus, with further reference to what has been disclosed above, according to an embodiment the first radio transceiver device <NUM> is, by the network node <NUM>, configured to select to use the second beam 160a, 160b for continued communications of radio signals with the second radio transceiver device <NUM> only when the link quality estimates of the second beam 160a, 160b are within the compensation value worse than the link quality estimates of the first beam 150a-<NUM>.

Thus, with further reference to what has been disclosed above, according to an embodiment the first radio transceiver device <NUM> is, by the network node <NUM>, configured to select to use the first beam 150a-<NUM> for continued communications of radio signals with the second radio transceiver device <NUM> when the link quality estimates of the second beam 160a, 160b are not within the compensation value worse than the link quality estimates of the first beam 150a-<NUM>.

One particular embodiment for beam selection and for configuring the first radio transceiver device <NUM> for beam selection based on at least some of the above disclosed embodiments will now be disclosed in detail.

S301: The network node <NUM> configures a TD RX beam training procedure and signals this to the first radio transceiver device <NUM>. One way to implement step S301 is to perform step S202.

S302: The first radio transceiver device <NUM> determines which TD RX beams to evaluate. Here, at least one of the TD RX beams has larger beamwidth compared to the remaining TD RX beams.

S303: The second radio transceiver device <NUM> transmits CSI-RSs according to the TD RX beam training configuration.

S304: The first radio transceiver device <NUM> sweeps through the determined TD RX beams and performs RSRP measurements on each one of them. One way to implement step S304 is to perform step S102.

S305: The first radio transceiver device <NUM> determines a compensation value based on different factors (see above for details).

S306: The first radio transceiver device <NUM> selects the best WD RX beam based on RSRP and the compensation value and uses the selected beam for coming downlink receptions (and optionally also as TD TX beam for uplink transmission). One way to implement step S306 is to perform any of steps S104, S104a, S104b, and S106.

<FIG> schematically illustrates, in terms of a number of functional units, the components of a radio transceiver device <NUM> according to an embodiment. Processing circuitry <NUM> is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1010a (as in <FIG>), e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry <NUM> is configured to cause the radio transceiver device <NUM> to perform a set of operations, or steps, S <NUM>-S <NUM>, S302, S304, S305, S306, as disclosed above. For example, the storage medium <NUM> may store the set of operations, and the processing circuitry <NUM> may be configured to retrieve the set of operations from the storage medium <NUM> to cause the radio transceiver device <NUM> to perform the set of operations. Thus the processing circuitry <NUM> is thereby arranged to execute methods as herein disclosed.

The radio transceiver device <NUM> may further comprise a communications interface <NUM> for communications at least with radio transceiver device <NUM> and network node <NUM>. As such the communications interface <NUM> may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry <NUM> controls the general operation of the radio transceiver device <NUM> e.g. by sending data and control signals to the communications interface <NUM> and the storage medium <NUM>, by receiving data and reports from the communications interface <NUM>, and by retrieving data and instructions from the storage medium <NUM>. Other components, as well as the related functionality, of the radio transceiver device <NUM> are omitted in order not to obscure the concepts presented herein.

<FIG> schematically illustrates, in terms of a number of functional modules, the components of a radio transceiver device <NUM> according to an embodiment. The radio transceiver device <NUM> of <FIG> comprises a number of functional modules; an obtain module 210a configured to perform step S <NUM> and a first select module 210b configured to perform step S104. The radio transceiver device <NUM> of <FIG> may further comprise a number of optional functional modules, such as any of a second select module 210c configured to perform step S 104a, a third select module 210d configured to perform step S 104b, and a communicate module 210e configured to perform step S106. In general terms, each functional module 210a-210e may be implemented in hardware or in software. Preferably, one or more or all functional modules 210a-210e may be implemented by the processing circuitry <NUM>, possibly in cooperation with the communications interface <NUM> and/or the storage medium <NUM>. The processing circuitry <NUM> may thus be arranged to from the storage medium <NUM> fetch instructions as provided by a functional module 210a-210e and to execute these instructions, thereby performing any steps of the radio transceiver device <NUM> as disclosed herein.

The radio transceiver device <NUM> may be provided as a standalone device or as a part of at least one further device. For example, as disclosed above the radio transceiver device <NUM> could be part of, integrated with, or collocated with, a terminal device.

<FIG> schematically illustrates, in terms of a number of functional units, the components of a network node <NUM> according to an embodiment. Processing circuitry <NUM> is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1010b (as in <FIG>), e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry <NUM> is configured to cause the network node <NUM> to perform a set of operations, or steps, S202, S301, S303, as disclosed above. For example, the storage medium <NUM> may store the set of operations, and the processing circuitry <NUM> may be configured to retrieve the set of operations from the storage medium <NUM> to cause the network node <NUM> to perform the set of operations. Thus the processing circuitry <NUM> is thereby arranged to execute methods as herein disclosed.

The network node <NUM> may further comprise a communications interface <NUM> for communications with radio transceiver device <NUM> and radio transceiver <NUM>. As such the communications interface <NUM> may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry <NUM> controls the general operation of the network node <NUM> e.g. by sending data and control signals to the communications interface <NUM> and the storage medium <NUM>, by receiving data and reports from the communications interface <NUM>, and by retrieving data and instructions from the storage medium <NUM>. Other components, as well as the related functionality, of the network node <NUM> are omitted in order not to obscure the concepts presented herein.

<FIG> schematically illustrates, in terms of a number of functional modules, the components of a network node <NUM> according to an embodiment. The network node <NUM> of <FIG> comprises a configure module 310a configured to perform step S202. The network node <NUM> of <FIG> may further comprise a number of optional functional modules, such as exemplified by module 310b. In general terms, each functional module 310a-310b may be implemented in hardware or in software. Preferably, one or more or all functional modules 310a-310b may be implemented by the processing circuitry <NUM>, possibly in cooperation with the communications interface <NUM> and/or the storage medium <NUM>. The processing circuitry <NUM> may thus be arranged to from the storage medium <NUM> fetch instructions as provided by a functional module 310a-310b and to execute these instructions, thereby performing any steps of the network node <NUM> as disclosed herein.

The network node <NUM> may be provided as a standalone device or as a part of at least one further device. For example, the network node <NUM> may be provided in a node of the radio access network or in a node of the core network. Alternatively, functionality of the network node <NUM> may be distributed between at least two devices, or nodes. These at least two nodes, or devices, may either be part of the same network part (such as the radio access network or the core network) or may be spread between at least two such network parts.

Thus, a first portion of the instructions performed by the network node <NUM> may be executed in a first device, and a second portion of the of the instructions performed by the network node <NUM> may be executed in a second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the network node <NUM> may be executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a network node <NUM> residing in a cloud computational environment. Therefore, although a single processing circuitry <NUM> is illustrated in <FIG> the processing circuitry <NUM> may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 310a-310b of <FIG> and the computer program 1020b of <FIG> (see below).

<FIG> shows one example of a computer program product 1010a, 1010b comprising computer readable means <NUM>. On this computer readable means <NUM>, a computer program 1020a can be stored, which computer program 1020a can cause the processing circuitry <NUM> and thereto operatively coupled entities and devices, such as the communications interface <NUM> and the storage medium <NUM>, to execute methods according to embodiments described herein. The computer program 1020a and/or computer program product 1010a may thus provide means for performing any steps of the radio transceiver device <NUM> as herein disclosed. On this computer readable means <NUM>, a computer program 1020b can be stored, which computer program 1020b can cause the processing circuitry <NUM> and thereto operatively coupled entities and devices, such as the communications interface <NUM> and the storage medium <NUM>, to execute methods according to embodiments described herein. The computer program 1020b and/or computer program product 1010b may thus provide means for performing any steps of the network node <NUM> as herein disclosed.

In the example of <FIG>, the computer program product 1010a, 1010b is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 1010a, 1010b could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 1020a, 1020b is here schematically shown as a track on the depicted optical disk, the computer program 1020a, 1020b can be stored in any way which is suitable for the computer program product 1010a, 1010b.

Claim 1:
A terminal device comprising a first radio transceiver device (<NUM>) for beam selection, the first radio transceiver device (<NUM>) comprising:
- processing circuitry (<NUM>) wherein the processing circuitry (<NUM>) comprises one or more processors for controlling operation of the first radio transceiver device;
- a communications interface (<NUM>), wherein the communications interface comprises one or more transmitters and receivers for communications of radio signals with a network node (<NUM>), the network node comprising a second radio transceiver device (<NUM>);
wherein the processing circuitry (<NUM>) is configured to cause the first radio transceiver device (<NUM>) to:
∘ obtain link quality estimates of a radio signal received through the communications interface (<NUM>) from the second radio transceiver device (<NUM>) in at least a first beam (150a-<NUM>) taken from a first beam set and in a second beam (160a, 160b), wherein the second beam (160a, 160b) is wider than the first beam (150a-<NUM>); and
∘ select which one of the first beam (150a-<NUM>) and the second beam (160a, 160b) to use for continued communications of radio signals with the second radio transceiver device (<NUM>) based on a comparison between the obtained link quality estimates of the first beam and the obtained link quality estimates of the second beam characterized in that the obtained link quality estimates of the second beam are increased with a compensation value.