Patent Publication Number: US-2023138221-A1

Title: Antenna arrangements for a radio transceiver device

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. application Ser. No. 17/006,288, filed Aug. 28, 2020, which is a continuation of U.S. application Ser. No. 15/543,539, filed Jul. 13, 2017, now U.S. Pat. No. 10,763,592, which is a 35 U.S.C. § 371 National Phase Entry Application from PCT/EP2017/065925, filed Jun. 27, 2017, designating the United States, the disclosures of each of the referenced applications are incorporated herein in their entirety by reference. 
    
    
     TECHNICAL FIELD 
     Embodiments presented herein relate to a method, a radio transceiver device, a computer program, and a computer program product for operating an antenna arrangement for transmission of a signal. Embodiments presented herein further relate to a method, a radio transceiver device, a computer program, and a computer program product for operating an antenna arrangement for reception of a signal. 
     BACKGROUND 
     In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed. 
     For example, for future generations of mobile communications systems frequency bands at many different carrier frequencies could be needed. For example, low such frequency bands could be needed to achieve sufficient network coverage for terminal devices and higher frequency bands (e.g. at millimeter wavelengths (mmW), i.e. near and above  30  GHz) could be needed to reach required network capacity. In general terms, at high frequencies the propagation properties of the radio channel are more challenging and beamforming both at the network node at the network side and at the terminal devices at the user side might be required to reach a sufficient link budget. 
     The terminal devices and/or the transmission and reception point (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. 
     For terminal devices the incoming signals might arrive from all different directions. Hence it is beneficial to have an antenna implementation at the terminal devices which has the possibility to generate omni-directional-like coverage in addition to the high gain narrow beams. One way to increase the omni-directional coverage at the terminal devices is to install multiple antenna arrays, and point the antenna arrays in mutually different directions.  FIG.  1    schematically illustrates a terminal device  100  comprising an antenna arrangement having two antenna arrays  120   a,    120   b,  each comprising antenna elements  140   a,    140   b  and phase shifters  130   a,    130   b.  Each antenna array  120   a,    120   b  is operatively connected to its own baseband (BB) chain  110   a,    110   b.  As the skilled person understands, the terminal device  100  could be provided with further antenna arrays, each having its own baseband chain, and each pointing in its own direction in order to further increase the omni-directional coverage. However, in order to limit the heat generated by the antenna arrangement the number of baseband chains should be kept small, for example by limiting the number of baseband chains to just two baseband chains. 
     With only two baseband chains, it could be challenging to design an antenna arrangement with high flexibility with respect to coverage and capacity (i.e. an antenna arrangement capable of generating both narrow beams and wide beams pointing different directions). 
     SUMMARY 
     An object of embodiments herein is to provide antenna arrangements that mitigate the deficiencies noted above and thus enable high flexibility with respect to coverage and capacity. 
     According to a first aspect there is presented an antenna arrangement for a radio transceiver device. The antenna arrangement comprises at least two antenna arrays, wherein at least one of the at least two antenna arrays has antenna elements of two polarizations. The antenna elements of one polarization at each of the at least two antenna arrays define a respective set of antenna elements. The antenna arrangement comprises at least two baseband chains. The antenna arrangement comprises a switching network configured to selectively operatively connect each of the at least two baseband chains with its own set of antenna elements such that no two baseband chains are operatively connected to one and the same set of antenna elements. Each of the at least one antenna array that has antenna elements of two polarizations is operatively connected to the switching network via a respective hybrid connector configured to provide a signal from one of the baseband chains to antenna elements of both polarizations. 
     Advantageously this antenna arrangement enables high flexibility with respect to coverage and capacity when transmitting and receiving signals. 
     Advantageously this antenna arrangement can be used in a terminal device for steering radiation pattern and baseband resources in different spatial directions, which will increase the coverage and/or capacity for the terminal device. 
     According to a second aspect there is presented a method for operating an antenna arrangement according to the first aspects for transmission of a signal. The method is performed by a radio transceiver device. The method comprises determining a setting according to which at least one of the baseband chains is operatively connected to the at least two antenna arrays baseband chains via the switching network when transmitting the signal. The method comprises obtaining the signal at the switching network from the at least one of the baseband chains. The method comprises providing the signal to at least one of the at least two antenna arrays in accordance with the setting, thereby transmitting the signal. 
     According to a third aspect there is presented a radio transceiver device for operating an antenna arrangement according to the first aspects for transmission of a signal. The radio transceiver device comprises processing circuitry. The processing circuitry is configured to cause the radio transceiver device to determine a setting according to which at least one of the baseband chains is operatively connected to the at least two antenna arrays via the switching network when transmitting the signal. The processing circuitry is configured to cause the radio transceiver device to obtain the signal at the switching network from the at least one of the baseband chains. The processing circuitry is configured to cause the radio transceiver device to provide the signal to at least one of the at least two antenna arrays in accordance with the setting, thereby transmitting the signal. 
     According to a fourth aspect there is presented a radio transceiver device for operating an antenna arrangement according to the first aspects for transmission of a signal. The radio transceiver device comprises processing circuitry and a storage medium. The storage medium stores instructions that, when executed by the processing circuitry, cause the radio transceiver device to perform operations, or steps. The operations, or steps, cause the radio transceiver device to determine a setting according to which at least one of the baseband chains is operatively connected to the at least two antenna arrays via the switching network when transmitting the signal. The operations, or steps, cause the radio transceiver device to obtain the signal at the switching network from the at least one of the baseband chains. The operations, or steps, cause the radio transceiver device to provide the signal to at least one of the at least two antenna arrays in accordance with the setting, thereby transmitting the signal. 
     According to a fifth aspect there is presented a radio transceiver device for operating an antenna arrangement according to the first aspects for transmission of a signal. The radio transceiver device comprises a determine module configured to determine a setting according to which at least one of the baseband chains is operatively connected to the at least two antenna arrays via the switching network when transmitting the signal. The radio transceiver device comprises an obtain module configured to obtain the signal at the switching network from the at least one of the baseband chains. The radio transceiver device comprises a provide module configured to provide the signal to at least one of the at least two antenna arrays in accordance with the setting, thereby transmitting the signal. 
     According to a sixth aspect there is presented a computer program for operating an antenna arrangement according to the first aspect for transmission of a signal. The computer program comprises computer program code which, when run on a radio transceiver device, causes the radio transceiver device to perform a method according to the first aspect. 
     According to a seventh aspect there is presented a method for operating an antenna arrangement according to the first aspects for reception of a signal. The method is performed by a radio transceiver device. The method comprises determining a setting according to which the at least two antenna arrays are to be operatively connected to at least one of the baseband chains via the switching network when receiving the signal. The method comprises obtaining the signal at the switching network from at least one of the at least two antenna arrays. The method comprises providing the signal to the at least one of the baseband chains in accordance with the setting, thereby receiving the signal. 
     According to an eighth aspect there is presented a radio transceiver device for operating an antenna arrangement according to the first aspects for reception of a signal. The radio transceiver device comprises processing circuitry. The processing circuitry is configured to cause the radio transceiver device to determine a setting according to which the at least two antenna arrays are to be operatively connected to at least one of the baseband chains via the switching network when receiving the signal. The processing circuitry is configured to cause the radio transceiver device to obtain the signal at the switching network from at least one of the at least two antenna arrays. The processing circuitry is configured to cause the radio transceiver device to provide the signal to the at least one of the baseband chains in accordance with the setting, thereby receiving the signal. 
     According to a ninth aspect there is presented a radio transceiver device for operating an antenna arrangement according to the first aspects for reception of a signal. The radio transceiver device comprises processing circuitry and a storage medium. The storage medium stores instructions that, when executed by the processing circuitry, cause the radio transceiver device to perform operations, or steps. The operations, or steps, cause the radio transceiver device to determine a setting according to which the at least two antenna arrays are to be operatively connected to at least one of the baseband chains via the switching network when receiving the signal. The operations, or steps, cause the radio transceiver device to obtain the signal at the switching network from at least one of the at least two antenna arrays. The operations, or steps, cause the radio transceiver device to provide the signal to the at least one of the baseband chains in accordance with the setting, thereby receiving the signal. 
     According to a tenth aspect there is presented a radio transceiver device for operating an antenna arrangement according to the first aspects for reception of a signal. The radio transceiver device comprises a determine module configured to determine a setting according to which the at least two antenna arrays are to be operatively connected to at least one of the baseband chains via the switching network when receiving the signal. The radio transceiver device comprises an obtain module configured to obtain the signal at the switching network from at least one of the at least two antenna arrays. The radio transceiver device comprises a provide module configured to provide the signal to the at least one of the baseband chains in accordance with the setting, thereby receiving the signal. 
     According to an eleventh aspect there is presented a computer program for operating an antenna arrangement according to the first aspect for transmission of a signal, the computer program comprising computer program code which, when run on a radio transceiver device, causes the radio transceiver device to perform a method according to the seventh aspect. 
     According to a twelfth aspect there is presented a computer program product comprising a computer program according to at least one of the sixth aspect and the eleventh 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. 
     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. 
     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 
       The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which: 
         FIG.  1    schematically illustrates a radio transceiver device and its antenna arrangement according to state of the art; 
         FIGS.  2  and  3    schematically illustrate antenna arrangements according to embodiments; 
         FIG.  4    schematically illustrates switching networks according to embodiments; 
         FIGS.  5  and  6    are flowcharts of methods according to embodiments; 
         FIG.  7    is a schematic diagram showing functional units of a radio transceiver device according to an embodiment; 
         FIG.  8    is a schematic diagram showing functional modules of a radio transceiver device according to an embodiment; and 
         FIG.  9    shows one example of a computer program product comprising computer readable storage medium according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
       FIG.  2    illustrates an embodiment of an antenna arrangement  300   a  for a radio transceiver device  200  according to an embodiment. The antenna arrangement  300   a  comprises two baseband chains  360   a,    360   b  and two antenna arrays  310   a,    310   b  with antenna elements  320  of two polarizations. The antenna elements  320  of one polarization at each of the antenna arrays  310   a,    310   b  define its own set of antenna elements. Each of the antenna arrays  310   a,    310   b  comprises antenna elements of two polarizations, and thus comprises two sets of antenna elements each. With two sets of antenna elements for each antenna array  310   a,    310   b  there is thus four sets of antenna elements in total in the antenna arrangement  300   a.    
     In the antenna arrangement  300   a  of  FIG.  2    the two antenna arrays  310   a,    310   b  have the same pointing direction, as symbolized by arrows  370   a,    370   b.  But as will be further disclosed below, in other examples at least two antenna arrays  310   a,    310   b  have mutually different pointing directions. 
     The antenna arrays  310   a,    310   b  are operatively connected to baseband chains  360   a,    360   b  via a switching network  350 , where B 1 , B 2  mark interfaces of the switching network  350  at the baseband side, and where A 1 , A 2  mark interfaces of the switching network  350  at the array side. 
     Each of the antenna arrays  310   a,    310   b  could, for each polarization, comprise an analog distribution network  380  to which the switching network  350  is operatively connected. The analog distribution network  380  thus connects the individual antenna elements  320  to the switching network  350 . 
     At the array side the switching network  350  is operatively connected to the antenna arrays  310   a,    310   b  via hybrid (H) connectors  340   a,    340   b.  Each output of the hybrid connector  340   a,    340   b  at the array side provides a signal from one of the baseband chains  360   a,    360   b  to antenna elements  320  of both polarizations. Each output of a respective hybrid connector  340   a,    340   b  at the array side is thus connected to a respective analog distribution network  380  serving antenna elements  320  of one polarization of one antenna array  310   a ,  310   b.    
     The switching network  350  comprises as many switches  355   a,    355   b  as there are baseband chains  360   a,    360   b  such that each baseband chain  360   a,    360   b  can be operatively connected to a respective one of the at least two antenna arrays  310   a,    310   b.  The switching network  350  thus provides baseband-to-array connections. Generally, only one of the baseband chains  360   a,    360   b  needs to be operatively connected to one of the antenna arrays  310   a,    310   b  in order for a signal to be transmitted or received by the antenna arrangement  300   a.  By means of the switching network  350  it is possible to configure baseband-to-array connections in different ways depending on how the switches  355   a,    355   b  are set. 
     According to a first example, the switches  355   a,    355   b  are set so as to connect B 1  with A 1  and B 2  with A 2 . Both baseband chains  360   a,    360   b  are thus connected to antenna array  310   a.  This setting can be useful, for example, if the radio transceiver device  200  is communicating with a TRP that is located in the same direction as this antenna array  310   a  is pointing in. 
     According to a second example, the switches  355   a,    355   b  are set so as to connect B 1  with A 3  and B 2  with A 4 . This setting is similar to the first example with the difference that both baseband chains  360   a,    360   b  are connected to antenna array  310   b.    
     According to a second example, the switches  355   a,    355   b  are set so as to connect B 1  with A 1  and B 2  with A 4 . Each baseband chain  360   a,    360   b  is thus connected to all antenna elements of its own antenna array  310   a,    310   b  through a respective one of the hybrid connectors  340   a,    340   b.  By using the hybrid connectors  340   a,    340   b,  the signal of each baseband chain  360   a,    360   b  will be provided to all antenna elements (of both polarizations) of a respective antenna array  310   a,    310   b,  which enables so-called dual-polarized beamforming within each panel antenna array  310   a,    310   b.  By using dual-polarized beamforming, almost arbitrarily beam widths could be attained for each respective antenna array  310   a,    310   b,  which will improve the transmission and reception performance of the radio transceiver device  200 . Details of dual-polarized beamforming are provided in documents WO2011/050866 A1 and WO2016141961 A1. 
     As will be further disclosed below, the antenna arrangement  300   a  could further comprise power amplifiers and/or low noise amplifiers  390  and phase shifters  330 . 
     The antenna arrangement  300   a  of  FIG.  2    is for simplicity illustrated to only comprise two antenna arrays  310   a,    310   b  with two antenna elements  320  each and comprising two baseband chains  360   a,    360   b.  Any number of antenna arrays  310   a,    310   b,  antenna elements  320 , and baseband chains  360   a,    360   b  can be used, and the antenna arrays  310   a,    310   b  could be either one-dimensional or two-dimensional antenna arrays. 
       FIG.  3    illustrates an embodiment of an antenna arrangement  300   b  for a radio transceiver device  200  according to another embodiment. The antenna arrangement  300   b  is similar to the antenna arrangement  300   a  and thus comprises two baseband chains  360   a,    360   b,  a switching network  350  with switches  355   a,    355   b,  and hybrid connectors  340   a,    340   b.  The antenna arrangement  300   b  comprises three antenna arrays  310   a,    310   b,    310   c,  all of which having mutually different pointing directions  370   a,    310   b,    370   c . Further, whilst antenna arrays  310   a,    310   b  have antenna elements  320  of two polarizations, antenna array  310   c  has antenna elements  320  of one polarization. 
     In view of the embodiments illustrated in  FIGS.  2  and  3    there is thus provided an antenna arrangement  300   a,    300   b  for a radio transceiver device  200 . The antenna arrangement  300   a,    300   b  comprises at least two antenna arrays  310   a,    310   b,    310   c.  At least one of the at least two antenna arrays  310   a,    310   b ,  310   c  has antenna elements  320  of two polarizations. The antenna elements  320  of one polarization at each of the at least two antenna arrays  310   a,    310   b ,  310   c  define a respective set of antenna elements  320 . 
     The antenna arrangement  300   a,    300   b  further comprises at least two baseband chains  360   a,    360   b.  In some aspects the antenna arrangement  300   a,    300   b  comprises precisely two baseband chains  360   a,    360   b.  Examples of switching networks  350  enabling the antenna arrangements to have more than two baseband chains  360   a,    360   b  will be disclosed below. 
     The antenna arrangement  300   a,    300   b  thus further comprises a switching network  350 . The switching network  350  is configured to selectively operatively connect each of the at least two baseband chains  360   a,    360   b  with its own set of antenna elements  320  such that no two baseband chains  360   a ,  360   b  are operatively connected to one and the same set of antenna elements  320 . In other words, the baseband chains  360   a,    360   b  are operatively connected to the antenna arrays  310   a,    310   b  such that the baseband chains  360   a,    360   b  do not share the same set of antenna elements  320  (where a set of antenna elements  320  is defined as above). 
     Each of the at least one antenna array  310   a,    310   b,    310   c  having antenna elements  320  of two polarizations is operatively connected to the switching network  350  via a respective hybrid connector  340   a,    340   b.  The hybrid connectors  340   a,    340   b  are configured to provide a signal from one of the baseband chains  360   a,    360   b  to antenna elements  320  of both polarizations. 
     Further aspects and embodiments relating to the antenna arrangement  300   a ,  300   b  will now be disclosed with parallel reference to the antenna arrangements  300   a,    300   b  of  FIGS.  2  and  3   . 
     In case the baseband chains  360   a,    360   b  are operatively connected to different sets of antenna elements  320  at one and the same antenna array, a signal transmitted from one of the baseband chains could be subjected to the inverse operations of the hybrid connector before being transmitted through the hybrid connector such as to cancel the effect of the hybrid connector and such that the signal from each baseband chain  360   a,    360   b  reaches a separate set of antenna elements  320  at the antenna array. Another alternative could be to selectively bypass the hybrid connectors  340   a,    340   b  when the baseband chains  360   a,    360   b  are operatively connected to different sets of antenna elements  320  at one and the same antenna array. 
     Aspects relating to configurations of the antenna arrays  310   a,    310   b,    310   c  will now be disclosed. 
     There could be different number of antenna arrays  310   a,    310   b,    310   c.  In some aspects there are only two antenna arrays  310   a,    310   b,    310   c.  In some embodiments the antenna arrangement  300   a,    300   b  comprises precisely two antenna arrays  310   a,    310   b,  where both antenna arrays  310   a,    310   b  have antenna elements  320  of two polarizations. The antenna arrangement  300   a  of  FIG.  2    is an example of such an embodiment. In some embodiments the antenna arrangement  300   a,    300   b  comprises a single antenna array  310   a ,  310   b  having antenna elements  320  of two polarizations and a single antenna array  310   c  having antenna elements  320  of one polarization. 
     The antenna arrays  310   a,    310   b,    310   c  might be one-dimensional or two-dimensional. In the examples of  FIGS.  2  and  3   , antenna arrays  310   a,    310   b  are one-dimensional whilst antenna array  310   c  is two-dimensional. That is, according to an embodiment the antenna arrangement  300   a,    300   b  comprises only one-dimensional antenna arrays or two-dimensional antenna arrays. In this respect the antenna arrangement  300   a  of  FIG.  2    is an example of an embodiment where the antenna arrangement  300   a  comprises only one-dimensional antenna arrays  310   a,    310   b.  According to another embodiment the antenna arrangement  300   a,    300   b  comprises a mix of at least one one-dimensional antenna array  310   c  and at least one two-dimensional antenna array  310   a,    310   b.  In this respect the antenna arrangement  300   a  of  FIG.  3    is an example of such an embodiment. 
     As disclosed above, each of the at least two antenna arrays  310   a,    310   b,    310   c  has a pointing direction  370   a,    370   b,    370   c.  The antenna arrays  310   a,    310   b ,  310   c  might point in the same direction or point in at least two directions. That is, according to an embodiment the at least two antenna arrays  310   a ,  310   b,    310   c  collectively has at least two mutually different pointing directions. In this respect the antenna arrangement  300   b  of  FIG.  3    is an example of an embodiment where the antenna arrays  310   a,    310   b,    310   c  point in three mutually different directions, according to the arrows  370   a,    310   b,    370   c.    
     As disclosed above, in some aspects each of the at least two antenna arrays  310   a,    310   b,    310   c  for each polarization comprises an analog distribution network  380  to which the switching network  350  is operatively connected. 
     As disclosed above, in some aspects the antenna arrangement  300   a,    300   b  comprises phase shifters  330 . There could be different placements of the phase shifters  330  in the antenna arrangements  300   a,    300   b.    
     In some aspects the phase shifters  330  are placed close to the antenna elements  320 . Thus, according to an embodiment each antenna element  320  has its own phase shifter  330 . In this respect the phase shifters  330  could be part of the analog distribution network  380 . 
     In other aspects the phase shifters  330  are placed close to the baseband. Thus, according to an embodiment the phase shifters  330  are operatively connected between the switching network  350  and the least two baseband chains  360   a,    360   b  such that there is one phase shifter  330  per baseband chain  360   a,    360   b.    
     As disclosed above, in some aspects the antenna arrangement  300   a,    300   b  comprises power amplifiers and/or low noise amplifiers  390 . There could be different placements of the power amplifiers and/or low noise amplifiers  390  in the antenna arrangements  300   a,    300   b.    
     In some aspects the power amplifiers and/or low noise amplifiers  390  are placed close to the antenna elements  320 . Thus, according to an embodiment each antenna element  320  has its own power amplifier and/or low noise amplifier  390 . In this respect the power amplifiers and/or low noise amplifiers  390  could be part of the analog distribution network  380 . 
     In other aspects the power amplifiers and/or low noise amplifiers  390  are placed close to the baseband. Thus, according to an embodiment the power amplifiers and low noise amplifiers  390  are operatively connected between the switching network  350  and the least two baseband chains  360   a,    360   b  such that there is one power amplifier and/or low noise amplifier per baseband chain  360   a,    360   b.    
     Possible placements of the phase shifters  330 , and power amplifiers and/or low noise amplifiers  390  have been indicated by arrows in  FIG.  2   . For simplicity, and to avoid cluttering in the drawings, the antenna arrangement  300   b  has in  FIG.  3    been illustrated without any phase shifters, power amplifiers, and low noise amplifiers. 
       FIG.  4    schematically illustrates different embodiments of the switching network  350 . As disclosed above, the switching network  350  comprises as many switches as there are baseband chains. However, for simplicity, the switching networks  350  have in  FIG.  4    been illustrated without switches. 
     The embodiment of  FIG.  4 ( a )  comprises three interfaces A 1 , A 2 , A 3  at the array side and two interfaces B 1 , B 2  at the baseband side. Two of the interfaces A 1 , A 2  are connected to a hybrid connector  340   a.  The embodiment of  FIG.  4 ( a )  is thus configured for an antenna arrangement having two baseband chains, one antenna arrays with antenna elements of two polarizations, and one antenna array with antenna elements of one polarization. 
     The embodiment of  FIG.  4 ( b )  comprises four interfaces A 1 , A 2 , A 3 , A 4  at the array side and two interfaces B 1 , B 2  at the baseband side. Two pairs of the interfaces (where A 1 , A 2  forms one pair and A 3 , A 4  forms another pair) are each connected to a respective hybrid connector  340   a,    340   b.  The embodiment of  FIG.  4 ( b )  is thus configured for an antenna arrangement having two baseband chains, and two antenna arrays with antenna elements of two polarizations. 
     The embodiment of  FIG.  4 ( c )  comprises five interfaces A 1 , A 2 , A 3 , A 4 , A 5  at the array side and three interfaces B 1 , B 2 , B 3  at the baseband side. Two pairs of the interfaces (where A 1 , A 2  forms one pair and A 3 , A 4  forms another pair) are each connected to a respective hybrid connector  340   a,    340   b.  The embodiment of  FIG.  4 ( c )  is thus configured for an antenna arrangement having three baseband chains, two antenna arrays with antenna elements of two polarizations, and one antenna array with antenna elements of one polarization. 
     There could be different examples of radio transceiver devices  200  in which the herein disclosed antenna arrangements  300   a,    300   b  could be provided. According to an embodiment the radio transceiver device  200  is a terminal device. Hence, in some aspects there is disclosed a radio transceiver device  200  comprising an antenna arrangement  300   a,    300   b  as herein disclosed. 
     The terminal device could, for example, be a portable wireless device, mobile station, mobile phone, handset, wireless local loop phone, user equipment (UE), smartphone, laptop computer, tablet computer, wireless modem, network equipped vehicle, network equipped sensor, or an Internet of Things (IoT) device. 
     Reference is now made to  FIG.  5    illustrating a method for operating any of the above disclosed antenna arrangements  300   a,    300   b  for transmission of a signal as performed by the radio transceiver device  200  according to an embodiment. 
     The antenna arrangement  300   a,    300   b  is configured according to how the signal is to be transmitted from the at least two antenna arrays  310   a,    310   b ,  310   c.  Thus, the radio transceiver device  200  is configured to perform step S 102 : 
     S 102 : The radio transceiver device  200  determines a setting according to which at least one of the baseband chains  360   a,    360   b  is operatively connected to a respective one of the at least two antenna arrays  310   a,    310   b ,  310   c  via the switching network  350  when transmitting the signal. In this respect, the conditions as defined above for how to operatively connect the antenna arrays  310   a,    310   b,    310   c  and the baseband chains  360   a,    360   b  still apply. Particularly, no two baseband chains  360   a,    360   b  are operatively connected to one and the same set of antenna elements. In one extreme case only a single baseband chain is operatively connected to a single one of the set of antennas. In the other extreme case each baseband chain is operatively connected to a respective one of the antenna arrays. The setting could define how the switches  355   a,    355   b  of the switching network  350  are set. 
     Once the switching network  350  has been properly set, the signal to be transmitted can be passed from the baseband side to the array side for transmission. Thus, the radio transceiver device  200  is configured to perform steps S 104 , S 106 : 
     S 104 : The radio transceiver device  200  obtains the signal at the switching network  350  from the at least one of the baseband chains  360   a,    360   b.    
     S 106 : The radio transceiver device  200  provides the signal to at least one of the at least two antenna arrays  310   a,    310   b,    310   c  in accordance with the setting. The signal is thereby transmitted. 
     Reference is now made to  FIG.  6    illustrating a method for operating any of the above disclosed antenna arrangements  300   a,    300   b  for reception of a signal as performed by the radio transceiver device  200  according to an embodiment. 
     The antenna arrangement  300   a,    300   b  is configured according to how the signal is to be received by the baseband chains  360   a,    360   b.  Thus, the radio transceiver device  200  is configured to perform step S 202 : 
     S 202 : The radio transceiver device  200  determines a setting according to which the at least two antenna arrays  310   a,    310   b,    310   c  are to be operatively connected to at least one of the baseband chains  360   a,    360   b  via the switching network  350  when receiving the signal. In this respect, the conditions as defined above for how to operatively connect the antenna arrays  310   a,    310   b ,  310   c  and the baseband chains  360   a,    360   b  still apply. Particularly, no two baseband chains  360   a,    360   b  are operatively connected to one and the same set of antenna elements. In one extreme case only a single baseband chain is operatively connected to a single one of the set of antennas. In the other extreme case each baseband chain is operatively connected to a respective one of the antenna arrays. The setting could define how the switches  355   a ,  355   b  of the switching network  350  are set. 
     Once the switching network  350  has been properly set, the signal to be received can be passed from the array side to the baseband side for reception. Thus, the radio transceiver device  200  is configured to perform steps S 204 , S 206 : 
     S 204 : The radio transceiver device  200  obtains the signal at the switching network  350  from at least one of the at least two antenna arrays  310   a,    310   b ,  310   c.    
     S 206 : The radio transceiver device  200  provides the signal to the at least one of the baseband chains  360   a,    360   b  in accordance with the setting. The signal is thereby received. 
       FIG.  7    schematically illustrates, in terms of a number of functional units, the components of a radio transceiver device  200  according to an embodiment. Processing circuitry  210  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  910  (as in  FIG.  9   ), e.g. in the form of a storage medium  230 . The processing circuitry  210  may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA). 
     Particularly, the processing circuitry  210  is configured to cause the radio transceiver device  200  to perform a set of operations, or steps, S 102 -S 106 , S 202 -S 206 , as disclosed above. For example, the storage medium  230  may store the set of operations, and the processing circuitry  210  may be configured to retrieve the set of operations from the storage medium  230  to cause the radio transceiver device  200  to perform the set of operations. The set of operations may be provided as a set of executable instructions. 
     Thus the processing circuitry  210  is thereby arranged to execute methods as herein disclosed. The storage medium  230  may also comprise persistent storage, which, for example, can be any single one or more combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. The radio transceiver device  200  may further comprise a communications interface  220 . The communications interface  220  could comprise an antenna arrangement  300   a,    300   b  as herein disclosed. 
     The processing circuitry  210  controls the general operation of the radio transceiver device  200  e.g. by sending data and control signals to the communications interface  220  and the storage medium  230 , by receiving data and reports from the communications interface  220 , and by retrieving data and instructions from the storage medium  230 . Other components, as well as the related functionality, of the radio transceiver device  200  are omitted in order not to obscure the concepts presented herein. 
       FIG.  8    schematically illustrates, in terms of a number of functional modules, the components of a radio transceiver device  200  according to an embodiment. In some aspects the radio transceiver device  200  of  FIG.  8    comprises a first determine module  210   a  configured to perform step S 102 , a first obtain module  210   b  configured to perform step S 104 , and a first provide module  210   c  configured to perform step S 106 . In some aspects the radio transceiver device  200  of  FIG.  8    comprises a second determine module  210   d  configured to perform step S 202 , a second obtain module  210   e  configured to perform step S 204 , and a second provide module  210   f  configured to perform step S 206 . 
     In general terms, each functional module  210   a - 210   f  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  230  which when run on the processing circuitry makes the radio transceiver device  200  perform the corresponding steps mentioned above in conjunction with  FIG.  8   . 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  210   a - 210   f  may be implemented by the processing circuitry  210 , possibly in cooperation with the communications interface  220  and/or the storage medium  230 . The processing circuitry  210  may thus be configured to form the storage medium  230  fetch instructions as provided by a functional module  210   a - 210   f  and to execute these instructions, thereby performing any steps as disclosed herein. 
       FIG.  9    shows one example of a computer program product  910   a,    910   b  comprising computer readable storage medium  930 . On this computer readable storage medium  930 , a computer program  920   a,    920   b  can be stored, which computer program  920   a,    920   b  can cause the processing circuitry  210  and thereto operatively coupled entities and devices, such as the communications interface  220  and the storage medium  230 , to execute methods according to embodiments described herein. The computer program  920   a,    920   b  and/or computer program product  910   a,    910   b  may thus provide means for performing any steps as herein disclosed. 
     In the example of  FIG.  9   , the computer program product  910   a,    910   b  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  910   a,    910   b  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  920   a,    920   b  is here schematically shown as a track on the depicted optical disk, the computer program  920   a,    920   b  can be stored in any way which is suitable for the computer program product  910   a,    910   b.    
     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.