Transceiver device with analog phase shifters
By adding phase offsets to ideal phase values before quantization, the method improves beamforming accuracy in transceiver devices, reducing grating lobes and pattern disturbances in hybrid beamforming systems without increasing component bits.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
- Filing Date
- 2024-11-18
- Publication Date
- 2026-05-21
AI Technical Summary
Existing transceiver devices face challenges in achieving improved beamforming accuracy without increasing the number of bits in components, particularly in hybrid beamforming systems, which leads to grating lobes and pattern disturbances due to quantization errors.
Implementing a method that adds a phase offset to ideal phase values before quantization in both analog and digital phase shifters, ensuring each subarray has a unique quantization error, thereby reducing grating lobes and pattern disturbances while maintaining a fixed number of bits.
Enhances beamforming accuracy by minimizing quantization errors and grating lobes, thus improving system performance without increasing component complexity.
Smart Images
Figure EP2024082704_21052026_PF_FP_ABST
Abstract
Description
[0001] TRANSCEIVER DEVICE WITH ANALOG PHASE SHIFTERS
[0002] TECHNICAL FIELD
[0003] Embodiments presented herein relate to a method, a transceiver device, a computer program, and a computer program product for transmitting a signal.
[0004] BACKGROUND
[0005] The demand for higher data rates and communication capacity is driving the use of new frequency bands at higher frequencies. These higher frequency bands introduce challenges related to the link budget, mainly due to increased pathloss. Pathloss, which rises with frequency, reduces signal strength over distance, requiring specific technical measures to maintain communication quality.
[0006] One common strategy in Active Antenna Systems (AAS) operating within the 6-7 GHz frequency bands is to maintain the antenna area of existing 3.5 GHz antennas. This approach helps achieve a similar link budget. However, because of the higher frequency, four times the number of antenna elements and radio branches are required compared to systems operating at 3.5 GHz. This increase brings about challenges in terms of system complexity, costs, and power requirements.
[0007] Frequency domain beamforming is a technology that directs signals to enhance system performance. However, when applied to higher frequencies and larger antenna arrays, frequency domain beamforming becomes costly.
[0008] To address the high costs and complexity of full frequency domain beamforming, hybrid beamforming is being explored. Hybrid beamforming combines frequency domain beamforming with analog beamforming to manage cost and complexity. Analog beamforming, in this setup, directs signals through simpler components like phase shifter circuits, which adjust the phase of signals in fixed steps based on a limited number of bits. This limited resolution of phase control can impact beamforming accuracy of the transceiver device in which the hybrid beamformer is implemented and, ultimately, system performance.
[0009] Hence, there is still a need for transceiver devices with improved beamforming accuracy. SUMMARY
[0010] An object of embodiments herein is to address the above issues and to enable the transceiver device to have improved beamforming accuracy.
[0011] A particular object is to provide a transceiver device having improved beamforming accuracy but without increasing the number of bits in the components of the transceiver device.
[0012] According to a first aspect there is presented a method for transmitting a signal from a transceiver device. The transceiver device comprises an antenna array having individually controllable subarrays. Each of the controllable subarrays is controllable by a respective digital phase shifter. Each of the controllable subarrays comprises fixed subarrays. Each of the fixed subarrays is controllable by a respective analog phase shifter. The method comprises obtaining an ideal phase value for each analog phase shifter. The method comprises quantizing each ideal phase value to a respective quantized phase value, with a phase offset value added to each ideal phase value before quantization. The method comprises applying each quantized phase value to its analog or digital phase shifter when using the antenna array for transmitting the signal from the transceiver device.
[0013] According to a second aspect there is presented a transceiver device for transmitting a signal. The transceiver device comprises processing circuitry and an antenna array. The antenna array has individually controllable subarrays. Each of the controllable subarrays is controllable by a respective digital phase shifter. Each of the controllable subarrays comprises fixed subarrays. Each of the fixed subarrays is controllable by a respective analog phase shifter. The processing circuitry is configured to cause the transceiver device to obtain an ideal phase value for each analog phase shifter. The processing circuitry is configured to cause the transceiver device to quantize each ideal phase value to a respective quantized phase value, with a phase offset value added to each ideal phase value before quantization. The processing circuitry is configured to cause the transceiver device to apply each quantized phase value to its analog or digital phase shifter when using the antenna array for transmitting the signal from the transceiver device. According to a third aspect there is presented a computer program for transmitting a signal. The computer program comprises computer code which, when run on processing circuitry of a transceiver device according to the second aspect, causes the transceiver device to perform actions. One action comprises the transceiver device to obtain an ideal phase value for each analog phase shifter. One action comprises the transceiver device to quantize each ideal phase value to a respective quantized phase value, with a phase offset value added to each ideal phase value before quantization. One action comprises the transceiver device to apply each quantized phase value to its analog or digital phase shifter when using the antenna array for transmitting the signal from the transceiver device.
[0014] According to a fourth aspect there is presented a computer program product comprising a computer program according to the third aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium.
[0015] Advantageously, these aspects enable the beamforming accuracy of the transceiver device to be improved, without increasing the number of bits in the components of the transceiver device.
[0016] Advantageously, these aspects enable the grating lobes for a transceiver device with hybrid beamforming to be reduced, whilst maintaining a fixed number of bits in resolution for the components of the transceiver device.
[0017] Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.
[0018] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, module, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:
[0020] Fig. 1 is a block diagram of an analog beamformer according to an embodiment;
[0021] Fig. 2 shows the phase error for an analog beamformer according to an embodiment;
[0022] Fig. 3 shows the farfield radiation pattern for an ideal analog beamformer and a quantized analog beamformer according to an embodiment;
[0023] Fig. 4 is a block diagram of an antenna array according to an embodiment;
[0024] Fig. 5 shows an array gain envelope according to an embodiment;
[0025] Fig. 6 is a flowchart of a method according to an embodiment;
[0026] Fig. 7 shows the resulting ideal and quantized phase according to an embodiment;
[0027] Fig. 8 shows subarray elevation patterns according to an embodiment;
[0028] Fig. 9 shows phase error of different subarrays according to an embodiment;
[0029] Fig. 10 shows the array gain envelope for ideal, quantized and quantized including a phase offset according to an embodiment;
[0030] Fig. 11 is a schematic diagram illustrating a communications system according to embodiments;
[0031] Fig. 12 is a schematic diagram showing structural units of a transceiver device according to an embodiment;
[0032] Fig. 13 is a schematic diagram showing functional modules of a transceiver device according to an embodiment; and
[0033] Fig. 14 shows one example of a computer program product comprising computer readable storage medium according to an embodiment. DETAILED DESCRIPTION
[0034] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.
[0035] As disclosed above, there is still a need for transceiver devices with improved beamforming accuracy.
[0036] A block diagram of an analog beamformer 100 comprising NFSAfixed subarrays 110a: 110 NFSAis provided in Fig. 1. Each fixed subarray noa:noAFSAcomprises of / ELantenna elements. The phase of each fixed subarray noa:noAFSAis controlled by a respective analog phase shifter i3oa:i3oAFSA. Each analog phase shifter has a resolution of m bits and P = 2mphase settings. The possible phase states of the phase shifters i30a:i30AFSAequals ypwhere the phase shifter least significant bit (Isb) equals ylsb= 360 ■ 2-m, and where
[0037] kp = (p - 1) ■ Yisb, p = l,..., P
[0038] For antenna systems with grid-of-beam implementation (as used in e.g., the third generation partnership (3GPP) codebook) a linear phase gradient is created over the aperture. The ideal phase, <pdeal, for fixed subarray number n can be expressed as follows.
[0039] <
[0040]
[0041] cleal= (n — 1) ■ k ■ dFSA■ sin(tilt), n = 1,..., NFSA,
[0042] where k = 2TT / A, where A is the wavelength of the signal to be transmitted, where dFSAis the distance between the center points of two adjacent fixed subarrays 110a: 110 NFSA, and where tilt is the desired down tilt angle (in degrees or radians). The quantized value of <phdealis defined as <p* = quantize [<p^deal], where quantize [<p^deal] is a quantization function operating on <p„deal. The quantized value equals the phase setting ypthat minimize the phase error |<p,ldeal- yp|. The maximum quantization error is thus equal to yisb / 2.
[0043] The resulting phase error for an analog beamformer 100 comprising NFSA= 12 fixed subarrays, each with a single antenna, with phase shifters having m bits is shown in Fig. 2. As can be seen in the figure, the phase error is periodic. A periodic error is equivalent to having large subarrays, which will create grating lobes i.e., a concentration of disturbed energy in a certain direction.
[0044] The corresponding farfield radiation pattern for an ideal analog beamformer 100 and the quantized analog beamformer 100 is presented in Fig.3. The impact of the quantization grating lobe can be observed at the 6 = 55 to 60 degree interval, where the quantized farfield radiation pattern is approximately 5 dB higher than the ideal farfield radiation pattern. The potential problem of the quantization phase error is not restricted to the grating lobe direction, even though the deviation is very clear here. In general, issues due to quantization error can occur in any direction and can be considered as a pattern disturbance compared to the ideal farfield radiation pattern.
[0045] A block diagram of an antenna array 400 comprising / VDSAindividually controllable subarrays 4ioa:4ioADSAis shown in Fig. 4. The individually controllable subarrays 4ioa:4ioADSAcan also be referred to as dynamic subarrays. Each individually controllable subarray 4ioa:4ioADSAis digitally controlled by the weights
[0046] w1(.. WNDSA, as implemented in digital phase shifters 43Oa:43OADSAof a digital beamformer 220. Each individually controllable subarray 4ioa:4ioADSAcomprises a respective analog beamformer as in Fig. 1.
[0047] The resulting array gain envelope GENVin dBi can be calculated as follows:
[0048] NDSA
[0049] dfiNV=dDSAm
[0050]
[0051] m=l from superposition, assuming that GDSA mcomes from the embedded pattern and that all individually controllable subarrays has a phase center in its own origin. The resulting array gain envelope is presented in Fig. 5. Since all individually controllable subarrays are identical the difference between Fig. 3 and Fig. 5 equals 10 logw(NDSA').
[0052] In summary, existing techniques for quantizing the ideal phase will provide periodic errors that can create grating lobes and relatively large disturbances on both individually controllable subarray level and on antenna array level. This can be a issue if e.g., low sidelobes are desired. Thus far the only available solution is to increase the number of bits m in the analog phase shifter i30a:i30NFSA. This increases the complexity of the antenna array 400.
[0053] The herein disclosed embodiments introduce individual phase offsets per individually controllable subarray. The phase offset will reduce the impact of the quantization error on antenna array level.
[0054] Fig. 6 is a flowchart illustrating embodiments of methods for transmitting a signal. The methods are performed by the transceiver device 1110, 1120. The methods are advantageously provided as computer programs. The transceiver device 1110, 1120 comprises an antenna array 400. The antenna array 400 has NDSAindividually controllable subarrays 4ioa:4ioNDSA. Each of the controllable subarrays 4ioa:4ioNDSAis controllable by a respective digital phase shifter 43oa:43oNDSA. Each of the controllable subarrays 4ioa:4ioNDSAcomprises NFSAfixed subarrays noa:iioNFSA. Each of the fixed subarrays noa:iioNFSAis controllable by a respective analog phase shifter i30a:i30NFSA,
[0055] S102: The transceiver device 1110, 1120 obtains an ideal phase value <phdealfor each analog phase shifter i30a:i30NFSA.
[0056] S104: The transceiver device 1110, 1120 quantizes each ideal phase value <p‘iclealto a respective quantized phase value
[0057]
[0058] with a phase offset value / ?madded to each ideal phase value <p„dealbefore quantization.
[0059] S106: The transceiver device 1110, 1120 applies each quantized phase value to its analog or digital phase shifter 43Oa:43ONDSAwhen using the antenna array 400, 1240 for transmitting the signal from the transceiver device 1110, 1120. Embodiments relating to further details of transmitting a signal as performed by the transceiver device 1110, 1120 will now be disclosed.
[0060] In some aspects, the transceiver device 1110, 1120 comprises a hybrid beamformer composed of a digital beamformer 420 and an analog beamformer 100. As in Fig. 1, the analog phase shifters i30a:i30AFSAare part of the analog beamformer 100. The analog phase shifters i30a:i30AFSAcan thus be regarded as analog phase shifter circuits with values ^uant,... <p^aaat. Further, as in Fig. 4, the digital phase shifters 430a:4301FSAare part of the digital beamformer 420. The digital phase shifter 43oa:43oADSAcan thus be regarded as defining the digital beamformer 420 with weig ohts w1ant’,...w NDuSaAnt-
[0061] As previously shown in Fig. 2, the quantization phase error is periodic and smaller or equal to ±yiSb / 2- According to an embodiment, a phase offset / ?mis added for individually controllable subarray m, to the ideal phase before quantization is performed. Hence, in some embodiments, the quantized phase values are implemented by the analog phase shifters i30a:i30AFSA, and the ideal phase value < Pndealis quantized according to:
[0062] < Pm,n = quantize [^deal+ / ?m]
[0063] where 1 < m < ADSA, where 1 < n < NFSA, and where quantize^] is a quantization function. One purpose of the phase offset / ?mis to avoid identical quantization error from all individually controllable subarrays. This is since identical individually controllable subarray will yield an array envelope with the same relative grating lobes as observed in Fig. 5.
[0064] The phase offset
[0065]
[0066] can be generated in different ways e.g., a randomized or optimized manner. In particular, in some embodiments, the phase offset value
[0067]
[0068] is determined according to:
[0069] oYlsb,, x Ylsb
[0070]
[0071] z l'lDSA1
[0072] where ylsb= 360 ■ 2k, and k is the number of bits used for quantizing the ideal phase value <p,‘ideal, and with m = 1,..., NDSA. Fig. 7 shows the resulting ideal and quantized phase using a phase offset (3mwhich varies linearly between —Yisb / 2'. and +yisb / 2 according to this equation. In other embodiments, the phase offset value / ?mis selected according to an optimization function. In yet other embodiments, the phase offset value / ?mis randomly selected in a predetermined interval.
[0073] The corresponding elevation patterns for the individually controllable subarrays after quantization based on the offset values / ?mare presented in Fig. 8. This figure shows that the elevation patterns for the individually controllable subarrays including the offset values / ?min the quantization are different. That is, the different quantization realizations create elevation pattern disturbances in different directions.
[0074] The phase offset may introduce a phase offset also on antenna array level. Let
[0075] ^m,n = arg(w) + <p^uant
[0076] denote the transmitted phase for individually controllable subarray m and fixed subarray n, and w equal the digital weights. The error can be compensated by adding the phase value
[0077]
[0078] to w. Hence, in some embodiments, a sum of a correction in the digital beamformer 420 and the ideal phase value <p‘iclealas quantized is obtained according to:
[0079] ^m,n = -Pm + quantize [<p^l eal+ / ?m]
[0080] where 1 < m < NDSA, where 1 < n < NFSA, and where quantize^] is a quantization function. The resulting phase error of the NDSAdifferent subarrays is calculated as <
[0081]
[0082] $>mn~ < Pndealand it is presented in Fig. 9.
[0083] The resulting array gain envelope for the ideal, the quantized and the quantized including a phase offset is presented in Fig. 10. The figure shows a small deviation between the ideal array gain envelope and the array gain envelope for the phase values quantized with phase offset. Thus, the disturbance caused by the quantization has been reduced using the herein disclosed embodiments. Further, the difference observed on individually controllable subarray level in Fig. 8 will average out on antenna array level (as illustrated in Fig. 10). It is noted that Figs. 2, 3, 5, 7, 8, 9, and 10 compare performance for one individually controllable subarray size and one individually controllable subarray tilt to illustrate different aspects of the herein disclosed inventive concept in a comparable manner. However, the performance will vary with individually controllable subarray size, tilt and directions.
[0084] Fig. 11 is a schematic diagram illustrating a communications system 1100 where embodiments presented herein can be applied. The communications system 1100 comprises a first transceiver device 1110 and a second transceiver device 1120. In the present example, the first transceiver device 1110 is, or is implemented as part of, a network node, such as a radio access network node, radio base station, base transceiver station, node B (NB), evolved node (eNB), gNB, transmission and reception point (TRP), integrated access and backhaul (IAB) node, or the like.
[0085] Further, the second transceiver device 1120 is, or is implemented as part of, a user equipment (UE), such as a portable wireless device, mobile station, mobile phone, handset, wireless local loop phone, smartphone, laptop computer, tablet computer, wireless mode device, network equipped vehicle, Internet of Things (loT) device, or the like.
[0086] Fig. 12 schematically illustrates, in terms of a number of structural units, the components of a transceiver device 1200 according to an embodiment. Processing circuitry 1210 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 1410 (as in Fig. 14), e.g. in the form of a storage medium 1230. The processing circuitry 1210 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).
[0087] Particularly, the processing circuitry 1210 is configured to cause the transceiver device 1200 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 1230 may store the set of operations, and the processing circuitry 1210 may be configured to retrieve the set of operations from the storage medium 1230 to cause the transceiver device 1200 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus the processing circuitry 1210 is thereby arranged to execute methods as herein disclosed. The storage medium 1230 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. The transceiver device 1200 may further comprise a communications (comm.) interface 1220 at least configured for communications with other entities, functions, nodes, and devices, such as another transceiver device, as in Fig. 11. As such the communications interface 1220 may comprise one or more transmitters and receivers, comprising analogue and digital components. The communications interface 1220 comprises an antenna array 1240 as herein disclosed.
[0088] The processing circuitry 1210 controls the general operation of the transceiver device 1200 e.g. by sending data and control signals to the communications interface 1220 and the storage medium 1230, by receiving data and reports from the communications interface 1220, and by retrieving data and instructions from the storage medium 1230. Other components, as well as the related functionality, of the transceiver device 1200 are omitted in order not to obscure the concepts presented herein.
[0089] Fig. 13 schematically illustrates, in terms of a number of functional modules, the components of a transceiver device 1300 according to an embodiment. The transceiver device 1300 of Fig. 13 comprises a number of functional modules; an obtain module 1310 configured to perform step S102, a quantize module 1320 configured to perform step S104, and an apply module 1330 configured to perform step S106. The transceiver device 1300 of Fig. 13 may further comprise a number of optional functional modules, as represented by functional module 1340. In general terms, each functional module 1310:1340 may in one embodiment be implemented only in hardware and in another embodiment with the help of software, i.e., the latter embodiment having computer program instructions stored on the storage medium 1230 which when run on the processing circuitry makes the transceiver device 1200, 1300 perform the corresponding steps mentioned above in conjunction with Fig 13. It should also be mentioned that even though the modules correspond to parts of a computer program, they do not need to be separate modules therein, but the way in which they are implemented in software is dependent on the programming language used. Preferably, one or more or all functional modules 1310:1340 may be implemented by the processing circuitry 1210, possibly in cooperation with the communications interface 1220 and / or the storage medium 1230. The processing circuitry 1210 may thus be configured to from the storage medium 1230 fetch instructions as provided by a functional module 1310:1340 and to execute these instructions, thereby performing any steps as disclosed herein.
[0090] The transceiver device 1200, 1300 may be provided as a standalone device or as a part of at least one further device. For example, the transceiver device 1200, 1300 may be provided in a network node or a UE, as in Fig. 11. Functionality of the transceiver device 1200, 1300 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 transceiver device 1200, 1300 may be executed in a first device, and a second portion of the of the instructions performed by the transceiver device 1200, 1300 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 transceiver device 1200, 1300 may be executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a transceiver device 1200, 1300 residing in a cloud computational environment. Therefore, although a single processing circuitry 1210 is illustrated in Fig. 12 the processing circuitry 1210 may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 1310:1340 of Fig. 13 and the computer program 1420 of Fig. 14.
[0091] Fig. 14 shows one example of a computer program product 1410 comprising computer readable storage medium 1430. On this computer readable storage medium 1430, a computer program 1420 can be stored, which computer program 1420 can cause the processing circuitry 1210 and thereto operatively coupled entities and devices, such as the communications interface 1220 and the storage medium 1230, to execute methods according to embodiments described herein. The computer program 1420 and / or computer program product 1410 may thus provide means for performing any steps as herein disclosed.
[0092] In the example of Fig. 14, the computer program product 1410 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 1410 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 1420 is here schematically shown as a track on the depicted optical disk, the computer program 1420 can be stored in any way which is suitable for the computer program product 1410.
[0093] The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.
Claims
CLAIMS1. A method for transmitting a signal from a transceiver device (1110, 1120, 1200, 1300), wherein the transceiver device (1110, 1120, 1200, 1300) comprises an antenna array (400, 1240) having NDSAindividually controllable subarrays (4ioa:4io7DSA), wherein each of the controllable subarrays (4ioa:4io7DSA) is controllable by a respective digital phase shifter (430a:4301DSA), wherein each of the controllable subarrays (4ioa:4io7DSA) comprises NFSAfixed subarrays (110a: 110 AFSA), wherein each of the fixed subarrays (110a: 110 AFSA) is controllable by a respective analog phase shifter (i30a:i301FSA), and wherein the method comprises:obtaining (S102) an ideal phase value <p‘iclealfor each analog phase shifter (13Oa:i3OAFSA);quantizing (S104) each ideal phase value <p„dealto a respective quantized phase value (Pm,n, with a phase offset value pmadded to each ideal phase value <p‘iclealbefore quantization; andapplying (S106) each quantized phase value to its analog or digital phase shifter (430a:4301DSA) when using the antenna array (400, 1240) for transmitting the signal from the transceiver device (1110, 1120, 1200, 1300).
2. The method according to claim 1, wherein the transceiver device (1110, 1120, 1200, 1300) comprises a hybrid beamformer composed of a digital beamformer (420) and an analog beamformer (100), and wherein the digital phase shifters (430a:4301FSA) are part of the digital beamformer (420) and the analog phase shifters (i30a:i301FSA) are part of the analog beamformer (100).
3. The method according to claim 1 or 2, wherein the quantized phase values are implemented by the analog phase shifters (i30a:i301FSA), and wherein the ideal phase value < Pndealis quantized according to:Pm,n = quantize [<p^deal+ / ?m]where 1 < m < ADSA, where 1 < n < NFSA, and where quantize^] is a quantization function.
4. The method according to claim 1 or 2, wherein a sum of a correction in the digital beamformer (420) and the ideal phase value <p‘iclealas quantized is obtained according to:^m,n = -Pm + quantize [<pnldeal+ / ?m]where 1 < m < NDSA, where 1 < n < NFSA, and where quantize^] is a quantization function.
5. The method according to any preceding claim, wherein the phase offset value / ?mis determined according to:oYlsb,, x YlsbPrn = ^-+ (m - l)- - —,z l'lDSA1where ylsb= 360 ■ 2k, and k is number of bits used for quantizing the ideal phase value < Pndeal-6. The method according to any of claims 1 to 4, wherein the phase offset valueis selected according to an optimization function.
7. The method according to any of claims 1 to 4, wherein the phase offset valueis randomly selected in a predetermined interval.
8. A transceiver device (1110, 1120, 1200, 1300) for transmitting a signal, the transceiver device (1110, 1120, 1200, 1300) comprising processing circuitry (1210) and an antenna array (400, 1240) having ADSAindividually controllable subarrays (4ioa:4io7DSA), wherein each of the controllable subarrays (4ioa:4io7DSA) is controllable by a respective digital phase shifter (430a:4301DSA), wherein each of the controllable subarrays (4ioa:4io7DSA) comprises AFSAfixed subarrays(110a: 110 AFSA), wherein each of the fixed subarrays (noa:iiolVFSA) is controllable by a respective analog phase shifter (130a: 130 AFSA), wherein the processing circuitry (1210) is configured to cause the transceiver device (1110, 1120, 1200, 1300) to:obtain an ideal phase value <p‘iclealfor each analog phase shifter (i30a:i301FSA);quantize each ideal phase value <p‘iclealto a respective quantized phase value< Pm,n’aphase offset value pmadded to each ideal phase value <p„dealbefore quantization; andapply each quantized phase value to its analog or digital phase shifter (43Oa:43ONDSA) when using the antenna array (400, 1240) for transmitting the signal from the transceiver device (1110, 1120, 1200, 1300).
9. The transceiver device (1110, 1120, 1200, 1300) according to claim 8, wherein the transceiver device (1110, 1120, 1200, 1300) comprises a hybrid beamformer composed of a digital beamformer (420) and an analog beamformer (100), and wherein the digital phase shifters (43Oa:43ONFSA) are part of the digital beamformer (420) and the analog phase shifters (i3Oa:i3ONFSA) are part of the analog beamformer (100).
10. The transceiver device (1110, 1120, 1200, 1300) according to claim 8 or 9, wherein the quantized phase values are implemented by the analog phase shifters (i3Oa:i3ONFSA), and wherein the ideal phase value <phdealis quantized according to:< Pm,n= quantize [<p^deal+ / ?m]where 1 < m < NDSA, where 1 < n < NFSA, and where quantize^] is a quantization function.n. The transceiver device (1110, 1120, 1200, 1300) according to claim 8 or 9, wherein a sum of a correction in the digital beamformer (420) and the ideal phase value <p‘idealas quantized is obtained according to:^m,n = ~Pm + quantize [<p^l eal+ / ?m]where 1 < m < NDSA, where 1 < n < NFSA, and where quantize^] is a quantization function.
12. The transceiver device (1110, 1120, 1200, 1300) according to any of claims 8 to 11, wherein the phase offset value pmis determined according to:Ylsb YlsbPm + (m — 1)2 NDSA ~ 1where ylsb= 360 ■ 2k, and k is number of bits used for quantizing the ideal phase value < Pndeal-13. The transceiver device (1110, 1120, 1200, 1300) according to any of claims 8 to 11, wherein the phase offset value / ?mis selected according to an optimization function.
14. The transceiver device (1110, 1120, 1200, 1300) according to any of claims 8 to 11, wherein the phase offset value / ?mis randomly selected in a predetermined interval.
15. A computer program (1420) for transmitting a signal, the computer program comprising computer code which, when run on processing circuitry (1210) of a transceiver device (1110, 1120, 1200, 1300) according to any of claims 8 to 14, causes the transceiver device (1110, 1120, 1200, 1300) to:obtain (S102) an ideal phase value <p„dealfor each analog phase shifter (13Oa:i3OAFSA);quantize (S104) each ideal phase value <p„dealto a respective quantized phase value with a phase offset value / ?madded to each ideal phase value <p‘iclealbefore quantization; andapply (S106) each quantized phase value to its analog or digital phase shifter (430a:4301DSA) when using the antenna array (400, 1240) for transmitting the signal from the transceiver device (1110, 1120, 1200, 1300).
16. A computer program product (1410) comprising a computer program (1420) according to claim 15, and a computer readable storage medium (1430) on which the computer program is stored.