Patent Publication Number: US-2023164737-A1

Title: Positioning

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to European Patent Application No. 21209413.0, filed Nov. 19, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNOLOGICAL FIELD 
     Embodiments of the present disclosure relate to positioning. Some relate to positioning in a wireless network. 
     BACKGROUND 
     A wireless network comprises a plurality of network nodes including terminal nodes and access nodes. Communication between the terminal nodes and the access nodes is wireless. 
     In some circumstances, it may be desirable to modify or enhance how a receiver device determines position information. 
     BRIEF SUMMARY 
     According to various, but not necessarily all, embodiments there is provided an apparatus comprising: 
     means for determining a plurality of beams; 
     means for combining received multipath signals from the plurality of the beams, the received multipath signals generated by a transmitter device; 
     means for determining, based at least in part on the combined received multipath signals, a line of sight signal; and 
     means for determining, based at least in part on the line of sight signal, position information of a receiver device. 
     In some examples, combining the received multipath signals from the plurality of the beams comprises determining a superimposed channel response for the plurality of beams. 
     In some examples, determining a line of sight signal comprises assuming that delays associated with the received multipath signals are on a grid having a resolution. 
     In some examples, the resolution is less than the sampling time. 
     In some examples, determining a line of sight signal comprises determining a first received multipath signal having energy above a threshold. 
     In some examples, determining a line of sight signal comprises employing a non-line-of-sight channel detector. 
     In some examples, the means are configured to: 
     determine a number of beams from which the received multipath signals are to be combined. 
     In some examples, determining a number of beams is based, at least in part, on one or more of: 
     a beam width of a main beam lobe and first side lobes; 
     the channel spread in the angle domain for multipath signals above a power threshold; 
     the channel spread in the angle domain for multipath signals below the power threshold. 
     According to various, but not necessarily all, embodiments there is provided an electronic device comprising an apparatus as described herein and a plurality of antennas. 
     According to various, but not necessarily all, embodiments there is provided a method comprising: 
     determining a plurality of beams; 
     combining received multipath signals from the plurality of the beams, the received multipath signals generated by a transmitter device; 
     determining, based at least in part on the combined received multipath signals, a line of sight signal; and 
     determining, based at least in part on the line of sight signal, position information of a receiver device. 
     In some examples, combining the received multipath signals from the plurality of the beams comprises determining a superimposed channel response for the plurality of beams. 
     In some examples, determining a line of sight signal comprises assuming that delays associated with the received multipath signals are on a grid having a resolution. 
     In some examples, the resolution is less than the sampling time. 
     In some examples, determining a line of sight signal comprises determining a first received multipath signal having energy above a threshold. 
     In some examples, determining a line of sight signal comprises employing a non-line-of-sight channel detector. 
     In some examples, the method comprises: 
     determining a number of beams from which the received multipath signals are to be combined. 
     In some examples, determining a number of beams is based, at least in part, on one or more of: 
     a beam width of a main beam lobe and first side lobes; 
     the channel spread in the angle domain for multipath signals above a power threshold; 
     the channel spread in the angle domain for multipath signals below the power threshold. 
     According to various, but not necessarily all, embodiments there is provided a computer program comprising instructions for causing an apparatus to perform: 
     determining a plurality of beams; 
     combining received multipath signals from the plurality of the beams, the received multipath signals generated by a transmitter device; 
     determining, based at least in part on the combined received multipath signals, a line of sight signal; and 
     determining, based at least in part on the line of sight signal, position information of a receiver device. 
     In some examples, combining the received multipath signals from the plurality of the beams comprises determining a superimposed channel response for the plurality of the beams. 
     In some examples, determining a line of sight signal comprises assuming that delays associated with the received multipath signals are on a grid having a resolution. 
     In some examples, the resolution is less than the sampling time. 
     In some examples, determining a line of sight signal comprises determining a first received multipath signal having energy above a threshold. 
     In some examples, determining a line of sight signal comprises employing a non-line-of-sight channel detector. 
     In some examples, the computer program comprising instructions for causing an apparatus to perform: 
     determining a number of beams from which the received multipath signals are to be combined. 
     In some examples, determining a number of beams is based, at least in part, on one or more of: 
     a beam width of a main beam lobe and first side lobes; 
     the channel spread in the angle domain for multipath signals above a power threshold; 
     the channel spread in the angle domain for multipath signals below the power threshold. 
     According to various, but not necessarily all, embodiments there is provided an apparatus comprising 
     at least one processor; and 
     at least one memory including computer program code; 
     the at least one memory and the computer program code configured to, with the at least on processor, cause the apparatus at least to perform at least a part of one or more methods disclosed herein. 
     According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for performing at least part of one or more methods disclosed herein. 
     According to various, but not necessarily all, embodiments there is provided examples as claimed in the appended claims. 
     The description of a function should additionally be considered to also disclose any means suitable for performing that function 
    
    
     
       BRIEF DESCRIPTION 
       Some examples will now be described with reference to the accompanying drawings in which: 
         FIG.  1    shows an example of the subject matter described herein; 
         FIG.  2    shows another example of the subject matter described herein; 
         FIG.  3    shows another example of the subject matter described herein; 
         FIG.  4    shows another example of the subject matter described herein; 
         FIG.  5    shows another example of the subject matter described herein; 
         FIG.  6    shows another example of the subject matter described herein; 
         FIG.  7    shows another example of the subject matter described herein; 
         FIG.  8    shows another example of the subject matter described herein; 
         FIG.  9    shows another example of the subject matter described herein; 
         FIG.  10 A  shows another example of the subject matter described herein; and 
         FIG.  10 B  shows another example of the subject matter described herein. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    illustrates an example of a network  100  comprising a plurality of network nodes including terminal nodes  110 , access nodes  120  and one or more core nodes  129 . The terminal nodes  110  and access nodes  120  communicate with each other. The one or more core nodes  129  communicate with the access nodes  120 . 
     The network  100  is in this example a telecommunications network, in which at least some of the terminal nodes  110  and access nodes  120  communicate with each other using transmission/reception of radio waves/signals. 
     The one or more core nodes  129  may, in some examples, communicate with each other. The one or more access nodes  120  may, in some examples, communicate with each other. 
     The one or more terminal nodes  110  may, in some examples, communicate with each other. 
     The network  100  may be a cellular network comprising a plurality of cells  122  at least one served by an access node  120 . In this example, the interface between the terminal nodes  110  and an access node  120  defining a cell  122  is a wireless interface  124 . 
     The access node(s)  120  is a cellular radio transceiver. The terminal nodes  110  are cellular radio transceivers. 
     In the example illustrated the cellular network  100  is a third generation Partnership Project (3GPP) network in which the terminal nodes  110  are user equipment (UE) and the access nodes  120  are base stations (for example, gNBs). 
     Functionality of a base station may be distributed between a central unit (CU), for example a gNB-CU, and one or more distributed units (DU), for example gNB-DUs. 
     In the particular example illustrated the network  100  is an Evolved Universal Terrestrial Radio Access network (E-UTRAN). The E-UTRAN comprises E-UTRAN NodeBs (eNBs), providing the E-UTRA user plane and control plane (for example, RRC) protocol terminations towards the UE. The eNBs  120  are interconnected with each other by means of an X2 interface  126 . The eNBs are also connected by means of the S1 interface  128  to the Mobility Management Entity (MME)  129 . 
     In other examples the network  100  is a Next Generation (or New Radio, NR) Radio Access network (NG-RAN). The NG-RAN comprises gNodeBs (gNBs), providing the user plane and control plane (for example, RRC) protocol terminations towards the UE. The gNBs are interconnected with each other by means of an X2/Xn interface  126 . 
     The gNBs are also connected by means of the N2 interface  128  to the Access and Mobility management Function (AMF). 
     In examples, the network  100  can comprise a combination of E-UTRAN and NG-RAN. 
     In examples, a terminal node  110  can be configured to perform and can perform dual active protocol stack handover from a first access node  120   a , which can be considered a source node, to a second access node  120   b , which can be considered a target node. 
     Some examples relate to a 3GPP network. 
     In examples a node, such as a terminal node  110 , can determine positioning information from received wireless signals. However, in examples, depending on the environment between a transmitting node and the terminal node  110 , the received wireless signals can comprise multipath signals. 
       FIG.  2    illustrates an example of a network  200 . 
     In the example of  FIG.  2   , the network  200  is a wireless network. In examples, the network  200  of  FIG.  2    can form part of and/or can communicate with the network  100  of  FIG.  1   . 
     In the example of  FIG.  2    a transmitter device  16  is wirelessly transmitting signals to an electronic device  32 , which can be considered a receiver device  21 . 
     In the example of  FIG.  2    the network  200  can comprise any suitable type of network  200 . In examples, the network can be considered a short range network. For example, the network  200  can have a range of up to 100 metres. 
     In the example of  FIG.  2    the transmitter device  16  and receiver device  21  are any suitable Wi-Fi devices. In examples, the transmitter device  16  and receiver device  21  can be considered Wi-Fi stations (STA). 
     In the example of  FIG.  2    there is an object  34  in the environment of the receiver device  21  and the signals from the transmitter device  16  take a line of sight (LOS) and non line of sight (NLOS) path to the receiver device. 
       FIG.  3    illustrates an example of a method  300 . 
     One or more of the features discussed in relation to  FIG.  3    can be found in one or more of the other FIGS. During discussion of  FIG.  3   , reference will be made to other FIGS. for the purposes of explanation. 
     In examples, method  300  can be performed by any suitable apparatus comprising any suitable means for performing the method  300 . 
     In examples, method  300  can be performed by any suitable node in network  100  and/or network  200 . For example, method  300  can be performed by any suitable node in network  100  and/or network  200  that receives wireless signals and determines position information. 
     For example, method  300  can be performed by a terminal node  110  of  FIG.  1    and/or receiver device  21  of  FIG.  2   . 
     In examples, method  300  can be considered a method  300  of determining position information  20 . 
     In examples, method  300  can be considered a method  300  of reducing errors in determining position information  20 . 
     In examples, method  300  can be considered a method  300  of mitigating ghost signals. 
     At block  302 , method  300  comprises determining a plurality of beams  12 . 
     In examples, determining a plurality of beams  12  can be performed in any suitable way using any suitable method. Any suitable number of beams  12  can be determined. 
     As used herein, the term “determining” (and grammatical variants thereof) can include, at least: calculating, computing, processing, deriving, investigating, looking up (for example, looking up in a table, a database or another data structure), and/or ascertaining. Also, “determining” can include receiving (for example, receiving information), and/or accessing (for example, accessing data in a memory). Also, “determining” can include resolving, selecting, choosing, and/or establishing. 
     In examples, the plurality of beams  12  can be considered a plurality of beamformers. 
     In examples, the plurality of beams  12  can be considered a plurality of reception beams  12  and/or reception beamformers. 
     In examples, a beam  12  can be considered to comprise any suitable information to be applied to signals received by a plurality of antenna elements. For example, a beam  12  can comprise a vector with complex entries that provide different weights to signals received by a plurality of antenna elements. 
     Accordingly, in examples, determining a plurality of beams comprises determining a plurality of vectors comprising complex entries that provide weights to signals received by a plurality of antenna elements. 
     In examples, determining a plurality of beams  12  comprises determining a plurality of adjacent beams  12 . 
     By way of example, reference is made to  FIG.  4   , which illustrates an example scenario. 
     In the example of  FIG.  4   , an electronic device  32 , which can be considered a receiver device  21 , has determined a plurality of beams  12 , which can be considered reception beams  12 . The beams  12  point in different directions. 
     In examples, the electronic device  32  can be considered an apparatus as described herein and/or an electronic device  32  comprising an apparatus as described herein. 
     Accordingly,  FIG.  4    illustrates an electronic device  32  comprising an apparatus as described herein. 
     In the example of  FIG.  4   , the reception beams  12 , formed by the determined signal weightings, are schematically illustrated and marked ‘A’ to ‘E’. The main lobe and first sidelobes of the beams  12  ‘A’ to ‘E’ are shown. 
     Although five beams  12  are shown in  FIG.  4   , in examples any suitable number of beams  12  can be determined. This is shown in the example of  FIG.  4    by the ellipses  36  at either end of the set of illustrated beams  12 . 
     In examples, the plurality of beams  12  determined at block  302  can be a subset of the total number of determined beams  12 . For example, in  FIG.  4    the beams ‘A’ to ‘E’ can be considered the plurality of beams  12 , or the beams ‘A’ to ‘C’ can be considered the plurality of beams  12  or the beams ‘B’ and ‘C’ can be considered the plurality of beams  12  or any suitable combination thereof. 
     In the example of  FIG.  4    a transmitter device  16  is transmitting signals to the receiver device  21 . 
     In the illustrated example, the signals can take multiple paths from the transmitter device  16  to the receiver device  21  and can therefore be considered multipath signals  14 . 
     In the illustrated example the line of sight (LOS) signal  18 , which is direct between the transmitter device  16  and the receiver device  21 , is indicated by a solid line and the non line of sight (NLOS) signals, which traverse, for example, via one or more reflections, are indicated by dashed lines. 
     In the example of  FIG.  4    it can be seen that the LOS signal  18  is received by a sidelobe of beam ‘C’ and NLOS signals are received by the mainlobes of beams ‘D’ and ‘E’. 
     This can cause problems, for example, for the receiver device  21  using the received signals to determine position information  20 . 
     Referring back to  FIG.  3   , at block  304  method  300  comprises combining received multipath signals  14  from the plurality of the beams  12 , the received multipath signals  14  generated by a transmitter device  16 . 
     In examples, combining received multipath signals  14  from the plurality of beams  12  can be performed in any suitable way using any suitable method. 
     In examples combining received multipath signals  14  can be considered merging and/or superimposing and/or integrating multipath signals  14  and so on. 
     In examples, combining received multipath signals  14  comprises and/or can be considered combining multipath information received by and/or via the plurality of beams  12 . 
     With reference to the example of  FIG.  4   , the multipath signals  14 , including the LOS signal  18 , received by the beams  12  of the receiver device  21  can be combined together. 
     That is, in the example of  FIG.  4   , information received by and/or via beams ‘A’ to ‘E’, or a subset thereof, can be combined together. 
     In examples, combining the received multipath signals  14  from the plurality of beams  12  comprises determining a superimposed channel response for the plurality of beams  12 . 
     In examples, method  300  comprises mapping the superimposed channel to a received super-vector. 
     In examples, combining the received multipath signals  14  from the plurality of beams  12  comprises mapping the superimposed channel to a received super-vector. 
     The following provides an example method for combining the received multipath signals  14 . 
     In examples, in combining received multipath signals  14 , it is assumed that a transmitter device  16 , which can be considered a positioning transmitter, is sending a known reference signal to a receiver device  21 , which can be considered a positioning receiver, over a multipath propagation, such as an indoor multipath propagation. See, for example, the example of  FIG.  4   . 
     The receiver device  21  has Nr antennas/antenna elements and applies a beam/beamformer W indexed u, that is. W u ∈C Nr  to capture the signal, where C Nr  is the complex vector space of ordered Nr-tuples of complex numbers. 
     After analogue to digital conversion, the baseband signal for beam/beamformer u, at each observed carrier k can be given by: 
         y   u   (k)   =W   u   H ( h   u   (k) ·1) s+n   u   (k) ,with  h   u   (k) =Σ l=1   Lu   a   u ( l )exp(−2π j k d   u ( l ))  [Eqn 1]
 
     where h u   (k)  is the frequency response of a beamed channel consisting of L u  multipath signals  14 , each arriving with a delay d u (l) and gain a u (l), s and n u  are the known Tx signal and the additive white gaussian noise respectively. ‘H’ used as a superscript denotes Hermitian operation. 
     U adjacent beams  12 , which can be considered the plurality of beams  12 , can be combined into a super-vector y (k)     T   , as follows: 
     
       
         
           
             
               
                 
                   
                     y 
                     
                       
                         ( 
                         k 
                         ) 
                       
                       T 
                     
                   
                   = 
                   
                     [ 
                     
                       
                         y 
                         
                           u 
                           - 
                           
                             U 
                             2 
                           
                           - 
                           1 
                         
                         
                           
                             ( 
                             k 
                             ) 
                           
                           T 
                         
                       
                       , 
                       … 
                           
                       , 
                       
                         y 
                         
                           u 
                           + 
                           
                             U 
                             2 
                           
                         
                         T 
                       
                     
                     ] 
                   
                 
               
               
                 
                   [ 
                   
                     Eqn 
                     ⁢ 
                         
                     2 
                   
                   ] 
                 
               
             
           
         
       
     
     Where ‘T’ denotes transpose. In examples, the number of beams  12  can be chosen such that the indices form whole numbers or a rounding function can be used on the indices. 
     In examples, the superimposed channel response h (k)  can be determined/estimated and can be defined as follows: 
     
       
         
           
             
               
                 
                   
                     h 
                     
                       ( 
                       k 
                       ) 
                     
                   
                   = 
                   
                     
                       h 
                       
                         u 
                         , 
                         
                           u 
                           - 
                           1 
                         
                         , 
                         
                           u 
                           + 
                           1 
                         
                         , 
                         … 
                       
                       
                         ( 
                         k 
                         ) 
                       
                     
                     = 
                     
                       
                         ∑ 
                         
                           l 
                           = 
                           1 
                         
                         L 
                       
                         
                       
                         
                           a 
                           ⁡ 
                           ( 
                           l 
                           ) 
                         
                         ⁢ 
                         
                           
                             exp 
                             ⁡ 
                             ( 
                             
                               - 
                               2 
                               ⁢ 
                               π 
                               ⁢ 
                               
                                 jkd 
                                 ⁡ 
                                 ( 
                                 l 
                                 ) 
                               
                             
                             ) 
                           
                           . 
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Eqn 
                     ⁢ 
                         
                     3 
                   
                   ] 
                 
               
             
           
         
       
     
     Accordingly, in some examples, combining the received multipath signals  14  from the plurality of the beams  12  comprises determining a superimposed channel response for the plurality of beams  12 . In examples, determining a superimposed channel response can be considered to form part of block  306 . 
     In examples, the superimposed channel maps to the received super-vector via y (k) , 
     
       
         
           
             
               
                 
                   
                     
                       y 
                       
                         ( 
                         k 
                         ) 
                       
                     
                     = 
                     
                       
                         Wh 
                         
                           ( 
                           k 
                           ) 
                         
                       
                       + 
                       n 
                     
                   
                   , 
                   
                     
                       where 
                       ⁢ 
                           
                       W 
                     
                     = 
                     
                       
                         [ 
                         
                           
                             W 
                             
                               u 
                               - 
                               
                                 U 
                                 2 
                               
                               - 
                               1 
                             
                             H 
                           
                           , 
                           … 
                               
                           , 
                           
                             W 
                             
                               u 
                               + 
                               
                                 U 
                                 2 
                               
                             
                             H 
                           
                         
                         ] 
                       
                       H 
                     
                   
                   , 
                 
               
               
                 
                   [ 
                   
                     Eqn 
                     ⁢ 
                         
                     4 
                   
                   ] 
                 
               
             
           
         
       
     
     and contains all the superimposition of the multipath signals  14  seen by the U adjacent beams/beamformers. 
     In examples, the matrix W in equation 4 can be considered a ‘mapper’ or a ‘projection’. 
     Referring again to the example of  FIG.  3   , at block  306  method  300  comprises determining, based, at least in part, on the combined received multipath signals  14 , a line of sight signal  18 . 
     In examples, determining, based, at least in part, on the combined received multipath signals  14 , a line of sight signal  18  can be performed in any suitable way using any suitable method. 
     In examples, determining, based, at least in part, on the combined received multipath signals  14 , a line of sight signal  18  comprises determining a line of sight signal  18  from combined multipath information received by and/or via the plurality of beams  12 . 
     With reference to the example of  FIG.  4   , the line of sight signal  18  is determined from the multipath signals  14  received by a plurality of beams  12  of the receiver device  21 . 
     In examples, a line of sight signal  18  can be considered a signal that travels directly from a transmitter device  16  to a receiver device  21 . 
     In examples, a line of sight signal  18  can be considered a signal that travels from a transmitter device  16  to a receiver device  21  without any redirections, such as reflections. 
     In examples, a line of sight signal  18  can be considered a direct path signal, a first signal and so on. 
     In examples, determining a line of sight signal  18  comprises assuming that delays  26  associated with the received multipath signals  14  are on a grid having a resolution  24 . 
     By way of example, reference is made to the example of  FIG.  5   . 
       FIG.  5    schematically illustrates a grid  22  of possible delays with a resolution  24 . The resolution  24  can be considered to be the period and/or distance between two points on the grid  22 . In the example of  FIG.  5   , time increases in the direction towards the right. 
     Any suitable resolution  24  can be used. In examples, the resolution  24  is less than the sampling time  30 . This is illustrated in the example of  FIG.  5    by the arrow, indicated as  30 , pointing to the right of  FIG.  5   . 
     In the example of  FIG.  5   , two of the points of the grid  22  have squares around them. This indicates that these points of the grid  22  have delays  26  associated with received multipath signals  14 . 
     Returning to  FIG.  3   , in examples, determining a line of sight signal  18  comprises determining a first received multipath signal  14  having energy above a threshold. 
     In examples, a first received multipath signal  14  can be considered a multipath signal  14  having the shortest associated delay. 
     In examples, the threshold can be considered a detection threshold, and any suitable threshold can be used. For example, the threshold can be defined as offset against the additive white gaussian noise of the superimposed channel, or empirically set, or selected based, at least in part, on the maximum multipath signal power, for example to be an amount below the maximum multipath signal power and so on. 
     In examples determining a line of sight signal  18  comprises employing and/or using a non line of sight channel detector. Any suitable non line of sight channel detector can be used. 
     The following provides an example method for determining, based at least in part on the combined received multipath signals  14 , a line of sight signal  18 . 
     To determine a line of sight signal  18 , h (k)  (see [Eqn 3] and [Eqn 4] can be determined/estimated by applying the gains and delay observed at each of the plurality of U beams into the superimposed beam, that is a=[a(1), . . . , a(L)] and d=[d(1), . . . , d(L)] in [Eqn 3]. 
     In examples, it is assumed that the delays can be approximated as lying on a grid with very fine resolution (that is ds&lt;&lt;Ts, where ds is the resolution and Ts is the sampling time of the system). 
     In some examples the grid length L is not longer than the symbol duration T, that is L=T/ds. However, in examples, the grid can have any suitable length. 
     Without loss of generality, it is assumed that delay d(l)=l·ds. That is, in examples, it is assumed that the delay of the l-th component d(I) is an integer multiple of the resolution ds. 
     For example, with regard to  FIG.  5   , it is assumed that the delays  26  indicated by the squares are integer values of possible delay values of the grid  22 . 
     Then, if the delay does not correspond or is not close to/is not in the neighborhood to a true channel multipath signal  14 , the gain a(I) will be determined/estimated as 0. This simplification reduces the channel reconstruction task to that of determining/estimating the complex entries of the vector a. 
     In examples, this can be performed using any suitable method. For example, this can be achieved with existing greedy approaches such as orthogonal matching pursuit-based algorithms. In examples, other approaches, such as Bayesian learning, can also be applied. 
     The line of sight signal  18  can then be determined. 
     In examples, the line of sight signal  18  is typically the first arriving multipath signal  14 , that is the first received multipath signal  14  with relevant energy, for example, x=min{1, . . . , L}, for which |a(x)|&gt;Γ, where Γ is the detection threshold. In examples, the detection threshold can be defined as offset against the AWGN n of the superimposed channel, or empirically set, or selected as the maximum tap power, or to be y dBs below maximum multipath signal power and so on. 
     In examples, line of sight signal  18  is not present in the channel associated with each beamformer u, which means that the beamformer/channel comprises only non line of sight signals and therefore can be marked as NLOS. 
     Accordingly, in examples, prior to determination of line of sight signal  18 , a NLOS channel detector may be employed. Any suitable NLOS detector can be used. For example a NLOS detector that makes use of the previous estimate a and computes a LOS probability or binary indicator, a NLOS detector that relies on hypothesis testing, and/or a NLOS detector that employs machine learning classifier such as decision forests. 
     In such examples, if the channel is deemed by the detector as LOS, then the line of sight signal determination follows. 
     In some examples, method  300  comprises determining relevant reflected multipath signals. 
     In examples, a multipath signal  14  can be considered relevant if the power of the multipath signal  14  is above a threshold. Any suitable threshold can be used. For example, the threshold can be determined based, at least in part, on the Rx noise floor, can be determined based, at least in part, on the maximum multipath signal power and so on. 
     At block  308 , method  300  comprises determining, based at least in part, on the line of sight signal  18 , position information  20  of a receiver device  21 . 
     Consequently,  FIG.  3    illustrates a method  300  comprising: 
     determining a plurality of beams  12 ;
 
combining received multipath signals  14  from the plurality of beams  12 , the received multipath signals  14  generated by a transmitter device  16 ;
 
determining, based at least in part on the combined received multipath signals, a line of sight signal  18 ; and
 
determining, based at least in part on the line of sight signal, position information  20  of a receiver device  21 .
 
     In examples the receiver device  21  is the device that performs method  300 . 
     In examples, determining, based at least in part of the line of sight signal  18 , position information  20  of a receiver device can be performed in any suitable way using any suitable method. 
     In examples, position information  20  of a receiver device  21  can comprise any suitable information to allow an absolute or relative position and/or location of a receiver device to be determined. For example, position information  20  can comprise angle of arrival and time of arrival of the line of sight signal  18 . 
     Accordingly, in examples, block  308  comprises determining, using any suitable method, angle of arrival and time of arrival of the line of sight signal  18 . 
     In examples, the time and angle of the line of sight signal is returned as: x·ds and ∠(a(x)), respectively. 
     In examples, method  300  comprises determining a number of beams  12  from which the received multipath signals  14  are to be combined. 
     In examples, determining a plurality of beams  12  comprises determining a number of beams  12  from which the received multipath signals  14  are to be combined. 
     Determining a number of beams  12  from which the received multipath signals  14  are to be combined can be performed in any suitable way using any suitable method. 
     In examples, determining a number of beams  12  is based, at least in part, on one or more of: a beam width B, b of a main beam lobe and first side lobes, the channel spread S in the angle domain for multipath signals  14  above a power threshold, and the channel spread s in the angle domain for multipath signals  14  below the power threshold. In examples, s can be considered a ‘tail spread’. 
     The beam width B, b of a main beam lobe and first side lobe can be considered the angular coverage of the main and first side lobes respectively. These are, in examples, antenna features and will be known be a receiver device  21 . 
     The channel spread S in the angle domain can be considered to be the difference between the narrowest and widest relevant reflection in the angle domain from a transmitter device  16 , a relevant reflection having power above a threshold. 
     The channel spread s in the angle domain can be considered to be the difference between the narrowest and widest reflection having power below the threshold. 
     In examples, an expected value for S and s can be determined from the channel models for which the method is being deployed, for example frequency-dependent indoor channel model. 
     In examples, method  300  comprises determining a sliding window size Z for determining how many beams  12  to skip for two consecutive beam bundles. 
     Accordingly, in examples, a number of adjacent beams  12  to be combined is determined and a number of beams to be skipped is determined. 
     By way of example, reference is made to  FIGS.  8  and  9   . 
       FIG.  8    illustrates an example of beam groupings. 
     In the example of  FIG.  8   , N beams are illustrated and two different bundles  34  of ‘U’ beams indicated by the dotted boxes. 
     In the illustrated example a first bundle  34  of two beams (beams  1  and  2 ) are to be combined and a second bundle  34  of two beams (beams  2  and  3 ) are to be combined. The bundles are separated by one beam (Z=1). 
       FIG.  9    illustrates an example of determination of a number of beams  12  and bundle separator Z. 
     In the example of  FIG.  9    f( )denotes a generic function of multiple variables. 
     At blocks  904 ,  910  and  914  of  FIG.  9    the known width of the first side lobe and the tail spread, s, is used to determine the slider Z. In the example of  FIG.  9    the function used is Z=min(b,s). 
     At blocks  902 ,  908  and  906  of  FIG.  9    the known width of the main lobe and the angular spread, S, is used to determine the number of beams  12 , represented by ‘U’. In the example of  FIG.  9    the function used is U=ceil(S/B). 
     In  FIG.  9    one or more channel modelling tools are used to determine S and s. 
     Examples of the disclosure are advantageous and provide technical benefits. 
     For example, examples of the disclosure allow a receiving device to mitigate the effect of non line of sight signals in determining position information. 
     Examples of the disclosure also provide a flexible approach in determining the line of sight signal, for example, the size of the grid, L, can be chosen based, at least in part, on the circumstances. 
       FIG.  6    illustrates an example of a method  600 . 
     In examples, the method  600  can be performed by any suitable apparatus comprising any suitable means for performing the method  600 . 
     In examples, method  600  can be performed by any suitable node in network  100  and/or network  200 . For example, method  600  can be performed by any suitable node in network  100  and/or network  200  that receives wireless signals and determines position information. 
     For example, method  600  can be performed by a terminal node  110  of  FIG.  1    and/or receiver device  21  of  FIG.  2   . 
     At blocks  602 ,  604  and  606  three beams  12  are determined, indicated as beam (u−1), beam (u) and beam (u+i). 
     At blocks  608 ,  610  and  612  multipath signals  14  are collected for the three beams, indicated as collect beamed signal (u−1), collect beamed signal (u) and collect beamed signal (u+i). 
     At block  614  the signals are combined and at block  616  the super-channel impulse response (SCIR(u−1, u, u+1) is initialized. 
     At block  618  the SCIR is detected and at block  620  the first path, or line of sight signal  18 , of the SCIR is selected. 
     At block  622  position information  20  of the first path of the SCIR is extracted. 
     In summary, in the method  600 , and/or in methods described herein, the channel impulse response (CIR) is estimated by combining the signals from at least three adjacent beams. 
     In other words, the received multipath signals as seen by any three (or more) adjacent beams are collected one super-channel impulse response (SCIR), corresponding to the superimposition of the three (or more) sparse channel responses associated with each of the beams, is estimated. 
     This prevents, for example, the receiver device  21  from misinterpreting the NLOS as LOS due to the beamforming gain of a sidelobe. 
     It can be considered that this approach corresponds to enhancing the main lobe (that is by combining the multiple narrow main lobes of the beamformers into a wider super-main lobe) and suppressing the sidelobes in the digital domain. 
     Once the SCIR is obtained, the angle and time of arrival of the first path of the SCIR are extracted and used for AOA- and/or TOA-based localization. 
       FIG.  7    illustrates an example of a method  700 . 
     In examples, the method  700  can be performed by any suitable apparatus comprising any suitable means for performing the method  700 . 
     In examples, method  700  can be performed by any suitable node in network  100  and/or network  200 . For example, method  600  can be performed by any suitable node in network  100  and/or network  200  that receives wireless signals and determines position information. 
     For example, method  700  can be performed by a terminal node  110  of  FIG.  1    and/or receiver device  21  of  FIG.  2   . 
     In examples, method  700  can be considered a method of determining, based at least in part on combined received multipath signals, a line of sight signal  18 . 
     At block  702 , the search space is selected. In the example of  FIG.  7    the resolution, ds, and length, L, of the grid  22  is determined. 
     At block  704 , the bundle size, U, of the plurality of beams  12  is selected and at block  708  mapper W is generated (see, for example, [Eqn 4]). 
     At block  706  received multipath signal samples are buffered and at block  710  super channel a is initialized. 
     Blocks  706 ,  708  and  710  feed into block  712  in which channel reconstruction method(s) are used and at block  714  a NLOS is optionally employed. 
     At block  716 , a direct path, or line of sight signal  18 , is detected and at block  718  position information  20  is extracted. 
     Examples of the disclosure provide technical benefits. For example, examples of the disclosure allow a receiver device to mitigate the effects of ghost signals during positioning. 
     Furthermore, examples of the disclosure provide a flexible method which can readily be adapted according to the circumstances. For example, the resolution ds and length L of the grid, and hence search space, can be flexibly changed according to circumstances. 
     Furthermore, examples of the disclosure can be used for channel equalisation for data decoding, for beam tracking, for beam selection in a subsequent uplink transmission and so on. 
       FIG.  10 A  illustrates an example of a controller  1130 . The controller can be used in any suitable apparatus to perform at least part of one of more methods described herein. In examples the apparatus can be used in a terminal node  110 , and/or an electronic device  32  and/or a receiver device  21  and/or a Wi-Fi device and/or a Wi-Fi station and so on. 
     In examples, controller  1130  can be considered an apparatus  1130 . 
     Implementation of a controller  1130  may be as controller circuitry. The controller  1130  may be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware). 
     As illustrated in  FIG.  10 A  the controller  1130  may be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program  1136  in a general-purpose or special-purpose processor  1132  that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor  1132 . 
     The processor  1132  is configured to read from and write to the memory  1134 . The processor  1132  may also comprise an output interface via which data and/or commands are output by the processor  1132  and an input interface via which data and/or commands are input to the processor  1132 . 
     The memory  1134  stores a computer program  1136  comprising computer program instructions (computer program code) that controls the operation of the apparatus when loaded into the processor  1132 . The computer program instructions, of the computer program  1136 , provide the logic and routines that enables the apparatus to perform the methods illustrated in  FIGS.  3  and/or  6  and/or  7  and/or  9   . The processor  1132  by reading the memory  1134  is able to load and execute the computer program  1136 . 
     The Apparatus Therefore Comprises: 
     at least one processor  1132 ; and
 
at least one memory  1134  including computer program code
 
the at least one memory  1134  and the computer program code configured to, with the at least one processor  1132 , cause the apparatus at least to perform:
 
     determining a plurality of beams; 
     combining received multipath signals from the plurality of the beams, the received multipath signals generated by a transmitter device; 
     determining, based at least in part on the combined received multipath signals, a line of sight signal; and 
     determining, based at least in part on the line of sight signal, position information of a receiver device. 
     As illustrated in  FIG.  10 A , the computer program  1136  may arrive at the apparatus via any suitable delivery mechanism  1162 . The delivery mechanism  1162  may be, for example, a machine readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a record medium such as a Compact Disc Read-Only Memory (CD-ROM) or a Digital Versatile Disc (DVD) or a solid state memory, an article of manufacture that comprises or tangibly embodies the computer program  1136 . The delivery mechanism may be a signal configured to reliably transfer the computer program  1136 . The apparatus may propagate or transmit the computer program  1136  as a computer data signal. 
     Computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: 
     determining a plurality of beams; 
     combining received multipath signals from the plurality of the beams, the received multipath signals generated by a transmitter device; 
     determining, based at least in part on the combined received multipath signals, a line of sight signal; and 
     determining, based at least in part on the line of sight signal, position information of a receiver device. 
     The computer program instructions may be comprised in a computer program, a non-transitory computer readable medium, a computer program product, a machine readable medium. In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program. 
     Although the memory  1134  is illustrated as a single component/circuitry it may be implemented as one or more separate components/circuitry some or all of which may be integrated/removable and/or may provide permanent/semi-permanent/dynamic/cached storage. 
     In examples the memory  1134  comprises a random-access memory  1158  and a read only memory  1160 . In examples the computer program  1136  can be stored in the read only memory  1158 . See, for example,  FIG.  10 B   
     In some examples the memory  1134  can be split into random access memory  1158  and read only memory  1160 . 
     Although the processor  1132  is illustrated as a single component/circuitry it may be implemented as one or more separate components/circuitry some or all of which may be integrated/removable. The processor  1132  may be a single core or multi-core processor. 
     References to ‘computer-readable storage medium’, ‘computer program product’, ‘tangibly embodied computer program’ etc. or a ‘controller’, ‘computer’, ‘processor’ etc. should be understood to encompass not only computers having different architectures such as single/multi-processor architectures and sequential (Von Neumann)/parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc. 
     As used in this application, the term ‘circuitry’ may refer to one or more or all of the following: 
     (a) hardware-only circuitry implementations (such as implementations in only analog and/or digital circuitry) and
 
(b) combinations of hardware circuits and software, such as (as applicable):
 
(i) a combination of analog and/or digital hardware circuit(s) with software/firmware and
 
(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and
 
(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g. firmware) for operation, but the software may not be present when it is not needed for operation.
 
This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.
 
     The blocks illustrated in the  FIGS.  3  and/or  6  and/or  9    may represent steps in a method and/or sections of code in the computer program  1136 . The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some blocks to be omitted. 
     Where a structural feature has been described, it may be replaced by means for performing one or more of the functions of the structural feature whether that function or those functions are explicitly or implicitly described. 
     The apparatus can, in examples, comprise means for: 
     determining a plurality of beams; 
     combining received multipath signals from the plurality of the beams, the received multipath signals generated by a transmitter device; 
     determining, based at least in part on the combined received multipath signals, a line of sight signal; and 
     determining, based at least in part on the line of sight signal, position information of a receiver device. 
     In examples, an apparatus can comprise means for performing one or more methods, and/or at least part of one or more methods, as disclosed herein. 
     In examples, an apparatus can be configured to perform one or more methods, and/or at least part of one or more methods, as disclosed herein. 
     The above described examples find application as enabling components of: automotive systems; telecommunication systems; electronic systems including consumer electronic products; distributed computing systems; media systems for generating or rendering media content including audio, visual and audio visual content and mixed, mediated, virtual and/or augmented reality; personal systems including personal health systems or personal fitness systems; navigation systems; user interfaces also known as human machine interfaces; networks including cellular, non-cellular, and optical networks; ad-hoc networks; the internet; the internet of things; virtualized networks; and related software and services. 
     The term ‘comprise’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use ‘comprise’ with an exclusive meaning then it will be made clear in the context by referring to “comprising only one.” or by using “consisting”. 
     In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term ‘example’ or ‘for example’ or ‘can’ or ‘may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus ‘example’, ‘for example’, ‘can’ or ‘may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class. It is therefore implicitly disclosed that a feature described with reference to one example but not with reference to another example, can where possible be used in that other example as part of a working combination but does not necessarily have to be used in that other example. 
     Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the claims. 
     Features described in the preceding description may be used in combinations other than the combinations explicitly described above. 
     Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. 
     Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not. 
     The term ‘a’ or ‘the’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a/the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use ‘a’ or ‘the’ with an exclusive meaning then it will be made clear in the context. In some circumstances the use of ‘at least one’ or ‘one or more’ may be used to emphasis an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning. 
     The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result. 
     In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described. 
     Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance it should be understood that the Applicant may seek protection via the claims in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not emphasis has been placed thereon.