Tracking reference signal and framework thereof in mobile communications
Techniques and examples of tracking reference signal and framework thereof in mobile communications are described. A user equipment (UE) receives, from a base station of a network, a reference signal via a communication link between the UE and the base station. The reference signal contains resource configuration with respect to tracking reference signal (TRS) configuration. The UE also receives, from the base station, a TRS burst containing a plurality of TRS symbols with one or more components of the UE configured according to the TRS configuration. The UE processes the TRS burst to perform channel estimation, synchronization, time tracking, frequency tracking, or a combination thereof.
1. A method, comprising:
receiving, by a processor of a user equipment (UE) from a base station of a network, a reference signal via a communication link between the UE and the base station, the reference signal containing resource configuration with respect to tracking reference signal (TRS) configuration;
receiving, by the processor from the base station, a TRS burst containing a plurality of TRS symbols with one or more components of the UE configured according to the TRS configuration; and
processing, by the processor, the TRS burst to perform channel estimation, synchronization, time tracking, frequency tracking, or a combination thereof,
wherein, in an event that the channel estimation comprises frequency offset estimation, the processing of the TRS burst to perform the channel estimation comprises performing the frequency offset estimation by extracting a phase difference between TRS resource elements (REs) in two of the plurality of TRS symbols that are in a same slot.
2. The method of claim 1 , wherein the channel estimation comprises one or more of time delay estimation, delay spread estimation, frequency offset estimation, and Doppler spread estimation.
3. The method of claim 1 , wherein a symbol spacing between two neighboring TRS symbols in the TRS burst is greater than or equal to 3 symbols, wherein the receiving of the TRS burst comprises receiving the plurality of TRS symbols of the TRS burst through a same antenna port of the UE, and wherein the plurality of TRS symbols occupy a same subcarrier location.
4. The method of claim 1 , wherein the processing of the TRS burst to perform the channel estimation comprises performing frequency offset estimation using two TRS symbols that are adjacent in a slot among the plurality of TRS symbols in the TRS burst.
5. The method of claim 1 , wherein the processing of the TRS burst to perform the channel estimation comprises performing frequency offset estimation using two TRS symbols that are non-adjacent in a slot among the plurality of TRS symbols in the TRS burst.
6. The method of claim 1 , wherein a pattern of the plurality of TRS symbols in the TRS burst is non-uniform.
7. The method of claim 1 , wherein the TRS configuration defines a plurality of parameters comprising:
X=a length of the TRS burst in terms of a number of 14-symbol slots;
Y=a periodicity of the TRS burst;
N=a number of orthogonal frequency-division multiplexing (OFDM) symbols occupied by one or more TRS symbol of the plurality of TRS symbols within each slot;
B=a TRS bandwidth in terms of a number of resource blocks (RBs);
S f =a TRS subcarrier spacing in a frequency domain; and
S t =a TRS symbol spacing between two neighboring TRS symbols of the plurality of TRS symbols in a time domain.
8. The method of claim 7 , wherein N=2, wherein there are fourteen OFDM symbols within each slot as denoted by symbol 0, symbol 1, symbol 2, symbol 3, symbol 4, symbol 5, symbol 6, symbol 7, symbol 8, symbol 9, symbol 10, symbol 11, symbol 12 and symbol 13, and wherein two of the fourteen OFDM symbols used for TRS comprise a pair of symbol 4 and symbol 8, a pair of symbol 5 and symbol 9, or a pair of symbol 6 and symbol 10.
9. The method of claim 7 , wherein, for the TRS burst, X=2, N 1 =2 for a first slot of the TRS burst, N 2 =2 for a second slot of the TRS burst, and there are four TRS symbols in the TRS burst (N total =4), wherein S t1 denotes a symbol spacing between a first TRS symbol in the first slot and a second TRS symbol in the first slot, wherein S t2 denotes a symbol spacing between the second TRS symbol in the first slot and a first TRS symbol in the second slot, wherein S t3 denotes a symbol spacing between the first TRS symbol in the second slot and a second TRS symbol in the second slot, and wherein S t2 is greater than or equal to S t3 which is greater than or equal to S t1 (S t2 >=S t3 >=S t1 ).
10. The method of claim 9 , wherein S t3 =S t1 .
11. The method of claim 9 , wherein S t3 >S t1 .
12. The method of claim 9 , wherein S t2 >=S t3 >S t1 .
13. The method of claim 7 , wherein, for the TRS burst, X=1, N 1 =2 for a first slot of the TRS burst and there are two TRS symbols in the TRS burst (N total =2), and wherein S t1 denotes a symbol spacing between a first TRS symbol in the first slot and a second TRS symbol in the first slot.
14. The method of claim 13 , wherein S t1 >=3.
15. An apparatus implementable in a user equipment (UE), comprising:
a transceiver capable of wirelessly communicating with a base station of a network; and
a processor coupled to the transceiver, the processor capable of performing operations comprising:
receiving, via the transceiver from the base station, a reference signal via a communication link between the UE and the base station, the reference signal containing resource configuration with respect to tracking reference signal (TRS) configuration;
receiving, via the transceiver from the base station, a TRS burst containing a plurality of TRS symbols with one or more components of the UE configured according to the TRS configuration; and
processing the TRS burst to perform channel estimation, synchronization, time tracking, frequency tracking, or a combination thereof,
wherein the processor receives the plurality of TRS symbols of the TRS burst through a same antenna port of the UE,
wherein the plurality of TRS symbols occupy a same subcarrier location, and
wherein, in an event that the channel estimation comprises frequency offset estimation, in processing the TRS burst to perform the channel estimation, the processor performs the frequency offset estimation by extracting a phase difference between TRS resource elements (REs) in two of the plurality of TRS symbols that are in a same slot.
16. The apparatus of claim 15 , wherein the channel estimation comprises one or more of time delay estimation, delay spread estimation, frequency offset estimation, and Doppler spread estimation, and wherein a symbol spacing between two neighboring TRS symbols in the TRS burst is greater than or equal to 3 symbols.
17. The apparatus of claim 15 , wherein the TRS configuration defines a plurality of parameters comprising:
X=a length of the TRS burst in terms of a number of 14-symbol slots;
Y=a periodicity of the TRS burst;
N=a number of orthogonal frequency-division multiplexing (OFDM) symbols occupied by one or more TRS symbol of the plurality of TRS symbols within each slot;
B=a TRS bandwidth in terms of a number of resource blocks (RBs);
S f =a TRS subcarrier spacing in a frequency domain; and
S t =a TRS symbol spacing between two neighboring TRS symbols of the plurality of TRS symbols in a time domain.
18. The apparatus of claim 17 , wherein N=2, wherein there are fourteen OFDM symbols within each slot as denoted by symbol 0, symbol 1, 2, 3, symbol 4, symbol 5, symbol 6, symbol 7, symbol 8, symbol 9, symbol 10, symbol 11, symbol 12 and symbol 13, and wherein two of the fourteen OFDM symbols used for TRS comprise a pair of symbol 4 and symbol 8, a pair of symbol 5 and symbol 9, or a pair of symbol 6 and symbol 10.
19. The apparatus of claim 17 , wherein, for the TRS burst, X=2, N 1 =2 for a first slot of the TRS burst, N 2 =2 for a second slot of the TRS burst, and there are four TRS symbols in the TRS burst (N total =4), wherein S t1 denotes a symbol spacing between a first TRS symbol in the first slot and a second TRS symbol in the first slot, wherein S t2 denotes a symbol spacing between the second TRS symbol in the first slot and a first TRS symbol in the second slot, wherein S t3 denotes a symbol spacing between the first TRS symbol in the second slot and a second TRS symbol in the second slot, and wherein S t2 is greater than or equal to S t3 which is greater than or equal to S t1 (S t2 >=S t3 >=S t1 ).
20. The apparatus of claim 17 , wherein, for the TRS burst, X=1, N 1 =2 for a first slot of the TRS burst and there are two TRS symbols in the TRS burst (N total =2), and wherein S t1 denotes a symbol spacing between a first TRS symbol in the first slot and a second TRS symbol in the first slot.