Positioning
An apparatus and method for position estimation are disclosed. The apparatus receives configuration information for a first Reference Signal (RS), and a second RS. The configuration information includes information indicative of a first and second time-frequency resource allocated to the first and second RS respectively. The allocation the resources is based on an estimate of a coherence time and a coherence bandwidth of a channel between the apparatus and a node. The apparatus receives the first and second RSs based on the configuration information and thereafter determines a phase offset between the received first and RSs. The first or second received RS are adjusted based on the phase offset and a third RS is generated for use in position estimation.
1 . An apparatus comprising:
at least one processor; and
at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:
receive configuration information for configuring the apparatus to receive a first Reference Signal (RS) and a second RS, wherein the configuration information comprises information indicative of:
a first time-frequency resource allocated to the first RS, and
a second time-frequency resource allocated to the second RS,
wherein an allocation of at least one of the first or second time-frequency resources is based, at least in part, on:
an estimate of a coherence time of a channel between the apparatus and a node of a Radio Access Network, and
an estimate of a coherence bandwidth of the channel;
receive, based at least in part on the configuration information, the first and second RSs;
determine a phase offset between the received first RS and the received second RS;
adjust a phase of at least one of the first and second received RSs based, at least in part, on the phase offset; and
generate a third RS for use in position estimation, wherein the apparatus generates the third RS based, at least in part, on:
one of the first and second RSs, and
an adjusted other of the first and second RSs.
2 . The apparatus of claim 1 , wherein a separation distance, in a time domain, between the first time-frequency resource and the second time-frequency resource is less than or equal to the estimate of the coherence time.
3 . The apparatus of claim 1 , wherein the configuration information configures the apparatus to receive the first and second RSs within a period of time that is less than or equal to the estimate of the coherence time.
4 . The apparatus of claim 1 , wherein a separation distance, in a frequency domain, between:
a frequency within one of the first and second time-frequency resources, and
a frequency within the other of the first and second time-frequency resources is less than or equal to the estimate of the coherence bandwidth.
5 . The apparatus of claim 1 , wherein the configuration information configures the apparatus to receive the first and second RSs over respective first and second frequency ranges, and
wherein an upper end of one of the first and second frequency ranges and a lower end of the other of the first and second frequency ranges are within a frequency bandwidth that is less than or equal to the estimate of the coherence bandwidth.
6 . The apparatus of claim 1 , wherein each of the received first RS and the received second RS comprises, in a frequency domain, a plurality of signal components associated with a respective plurality of frequencies, and
wherein the instructions, when executed by the at least one processor, further cause the apparatus at least to:
select a first signal component of the first RS and a second signal component of the second RS whose respective associated frequencies are separated by less than or equal to the estimate of the coherence bandwidth;
determine a first phase value for the first signal component;
determine a second phase value for the second signal component; and
define the phase offset based, at least in part, on a difference between the first and second phase values.
7 . The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus at least to:
determine a difference between a time of reception of the first RS and a time of reception of the second RS; and
determine a phase shift between the received first RS and the received second RS based, at least in part, on the difference in the time of the reception of the first RS and the time of the reception of the second RS.
8 . The apparatus of claim 7 , wherein adjusting the phase of the at least one of the first and second received RSs comprises adjusting the phase of the at least one of the first and second received RSs based, at least in part, on the phase shift.
9 . The apparatus of claim 7 , wherein generating the third RS is further based, at least in part, on the phase shift.
10 . The apparatus of claim 1 , wherein the first RS has a first bandwidth, and the second RS has a second bandwidth, and wherein the third RS has a third bandwidth greater than each of the first and second bandwidths.
11 . The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus at least to:
perform at least one measurement on the generated third RS; and
send a measurement result of the at least one measurement performed on the generated third RS.
12 . A method comprising:
receiving configuration information for configuring an apparatus to receive a first Reference Signal (RS) and a second RS, wherein the configuration information comprises information indicative of:
a first time-frequency resource allocated to the first RS, and
a second time-frequency resource allocated to the second RS,
wherein an allocation of at least one of the first or second time-frequency resources is based, at least in part, on:
an estimate of a coherence time of a channel between the apparatus and a node of a Radio Access Network, and
an estimate of a coherence bandwidth of the channel;
receiving, based at least in part on the configuration information, the first and second RSs;
determining a phase offset between the received first RS and the received second RS;
adjusting a phase of at least one of the first and second received RSs based, at least in part, on the phase offset; and
generating a third RS for use in position estimation, wherein the third RS is generated based, at least in part, on:
one of the first and second RSs, and
an adjusted other of the first and second RSs.
13 . The method of claim 12 , wherein a separation distance, in a time domain, between the first time-frequency resource and the second time-frequency resource is less than or equal to the estimate of the coherence time.
14 . The method of claim 12 , wherein the configuration information configures the apparatus to receive the first and second RSs within a period of time that is less than or equal to the estimate of the coherence time.
15 . The method of claim 12 , wherein a separation distance, in a frequency domain, between:
a frequency within one of the first and second time-frequency resources, and
a frequency within the other of the first and second time-frequency resources is less than or equal to the estimate of the coherence bandwidth.
16 . The method of claim 12 , wherein the configuration information configures the apparatus to receive the first and second RSs over respective first and second frequency ranges, and
wherein an upper end of one of the first and second frequency ranges and a lower end of the other of the first and second frequency ranges are within a frequency bandwidth that is less than or equal to the estimate of the coherence bandwidth.
17 . The method of claim 12 , wherein each of the received first RS and the received second RS comprises, in a frequency domain, a plurality of signal components associated with a respective plurality of frequencies, and
wherein the method further comprises:
selecting a first signal component of the first RS and a second signal component of the second RS whose respective associated frequencies are separated by less than or equal to the estimate of the coherence bandwidth;
determining a first phase value for the first signal component;
determining a second phase value for the second signal component; and
defining the phase offset based, at least in part, on a difference between the first and second phase values.
18 . The method of claim 12 , further comprising:
determining a difference between a time of reception of the first RS and a time of reception of the second RS; and
determining a phase shift between the received first RS and the received second RS based, at least in part, on the difference in the time of the reception of the first RS and the time of the reception of the second RS.
19 . The method of claim 18 , further comprising:
adjusting the phase of at least one of the first and second received RSs based, at least in part, on the phase shift.
20 . A non-transitory computer program product comprising instructions, which when executed by an apparatus, cause the apparatus to perform:
receiving configuration information for configuring the apparatus to receive a first Reference Signal (RS) and a second RS, wherein the configuration information comprises information indicative of:
a first time-frequency resource allocated to the first RS, and
a second time-frequency resource allocated to the second RS,
wherein an allocation of at least one of the first or second time-frequency resources is based, at least in part, on:
an estimate of a coherence time of a channel between the apparatus and a node of a Radio Access Network, and
an estimate of a coherence bandwidth of the channel;
receiving, based at least in part on the configuration information, the first and second RSs;
determining a phase offset between the received first RS and the received second RS;
adjusting a phase of at least one of the first and second received RSs based, at least in part, on the phase offset; and
generating a third RS for use in position estimation, wherein the third RS is generated based, at least in part, on:
one of the first and second RSs, and
an adjusted other of the first and second RSs.