GENERATING AND TRANSMITTING DEMODULATION REFERENCE SIGNALS

• US 20160316459A1
• Filed: 06/30/2016
• Published: 10/27/2016
• Est. Priority Date: 01/13/2012
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: POPOVIC, Branislav, SUN, Weijun
• Granted Patent: US 10,098,104 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

The present disclosure provides a solution which solves the problem of demodulation reference signal (DMRS) ambiguity by introducing separate, i.e. different DMRSs. This is especially the case for systems employing dynamic allocation of control and data signals to different PRBs.

Claims

1. A method in a receiver node adapted for communication in a wireless communication system, said wireless communication system being adapted for using time-frequency resource elements for transmission of information;

said method comprising the steps of;

receiving at least one receiver specific control channel signal (e-PDCCH) and an associated second receiver specific demodulation reference signal (e-PDCCH-DMRS);

receiving at least one receiver specific data channel signal (PDSCH) and an associated first receiver specific demodulation reference signal (PDSCH-DMRS);

demodulating said receiver specific control channel signal (e-PDCCH) by using said associated second receiver specific demodulation reference signal (e-PDCCH-DMRS); and

using information derived from said step of demodulating said receiver specific control channel signal (e-PDCCH) for demodulating said receiver specific data channel signal (PDSCH).

2. The method according to claim 1, further comprising the step of:

searching for said second receiver specific demodulation reference signal (e-PDCCH-DMRS) in all physical resource blocks (PRBs) within a given time-frequency search space so as to identify physical resource blocks (PRBs) allocated for receiver specific control channel signals (e-PDCCHs).

3. The method according to claim 2, wherein said wireless communication system employs multiple antenna port transmissions, and said step of searching further involves:

searching in all antenna ports that are used for transmission of said second receiver specific demodulation reference signal (e-PDCCH-DMRS).

4. The Method according to claim 2, wherein said step of searching involves:

identifying a set of candidate receiver specific control channel signal (e-PDCCH) physical resource block (PRB) pairs by searching said given time-frequency search space; and

demodulating and performing CRC check for candidates in said set, and if a CRC check is positive for a candidate assume that said candidate is correct.

5. The Method according to claim 4, further comprising the step of:

performing blind detection on remaining receiver specific control channel signal (e-PDCCH) physical resource block (PRB) pairs in said given time-frequency search space if step ii) does not result in a positive CRC check.

6. The Method according to claim 3, wherein said step of searching involves:

identifying a set of candidate receiver specific control channel signal (e-PDCCH) physical resource block (PRB) pairs by searching said given time-frequency search space; and

demodulating and performing CRC check for candidates in said set, and if a CRC check is positive for a candidate assume that said candidate is correct.

7. The Method according to claim 6, further comprising the step of:

performing blind detection on remaining receiver specific control channel signal (e-PDCCH) physical resource block (PRB) pairs in said given time-frequency search space if step ii) does not result in a positive CRC check.

8. Method according to claim 1, wherein said receiver node is a mobile station.

9. An apparatus, comprising:

a memory storing instructions related to;

receiving at least one receiver specific control channel signal (e-PDCCH) and an associated second receiver specific demodulation reference signal (e-PDCCH-DMRS);

receiving at least one receiver specific data channel signal (PDSCH) and an associated first receiver specific demodulation reference signal (PDSCH-DMRS);

demodulating said receiver specific control channel signal (e-PDCCH) by using said associated second receiver specific demodulation reference signal (e-PDCCH-DMRS); and

using information derived from said step of demodulating said receiver specific control channel signal (e-PDCCH) for demodulating said receiver specific data channel signal (PDSCH); and

a processor, coupled to the memory, configured to execute the instructions stored in the memory.

10. The apparatus according to claim 9, wherein the apparatus is a mobile station.

11. An apparatus, comprising:

a processor, configured to generate at least one first receiver specific demodulation reference signal (PDSCH-DMRS) associated with a receiver specific data channel signal (PDSCH), and generate at least one second receiver specific demodulation reference signal (e-PDCCH-DMRS) associated with a receiver specific control channel signal (e-PDCCH); and

a transmitter, configured to transmit said receiver specific control channel signal (e-PDCCH) concurrently with said associated second receiver specific demodulation reference signal (e-PDCCH-DMRS), and transmit said receiver specific data channel signal (PDSCH) concurrently with said associated first receiver specific demodulation reference signal (PDSCH-DMRS).

12. The apparatus according to claim 11, wherein the processor is further configured to:

dynamically allocate said receiver specific data channel signal (PDSCH) and said receiver specific control channel signal (e-PDCCH) to different physical resource blocks (PRBs).

13. The apparatus according to claim 12, wherein said first receiver specific demodulation reference signal (PDSCH-DMRS) is generated by using a first sequence of symbols {a_p(k)}, k=0, 1, . . . , L−

1 for modulating time-frequency resource elements (REs) at fixed positions within physical resource blocks (PRBs) used for transmission of data channel signals (PDSCHs) at a transmit antenna port p; and

said second receiver specific demodulation reference signal (e-PDCCH-DMRS) is generated by using a second sequence of symbols {b_u,p(k)}, k=0, 1, . . . , L−

1 for modulating time-frequency resource elements (REs) at fixed positions within physical resource blocks (PRBs) used for transmission of receiver specific control channel signals (e-PDCCHs) at a transmit antenna port p, said second sequence of symbols {b_u,p(k)} being a u-th sequence from a set of U sequences that can be allocated to one or more receiver nodes in said wireless communication system.

14. The apparatus according to claim 13, wherein said first sequence of symbols {a_p(k)}, k=0, 1, . . . , L−

1 is different from said second sequence of symbols {b_u,p(k)}, k=0, 1, . . . , L−

1.

15. The apparatus according to claim 14, wherein said first sequence of symbols {a_p(k)}, k=0, 1, . . . , L−

1 is defined as;

a_p(k)=w_p(k)q(n_PRB,k), k=0, 1, . . . , 11, where q(n_PRB,k) is a physical resource block (PRB) scrambling sequence according to 3GPP LTE standard.

16. The apparatus according to claim 14, wherein the processor is configured to obtain said second sequence of symbols {b_u,p(k)}, k=0, 1, . . . , L−

1 by;

multiplying, symbol-by-symbol, said first sequence of symbols {a_p (k)}, k=0, 1, . . . , L−

1 with a receiver specific signature sequence {s_u(k)}, k=0, 1, . . . , L−

1 so that b_u,p(k)=a_p(k)s_u(k), k=0, 1, . . . , L−

1, said receiver specific signature sequence {s_u(k)} being a u-th sequence from a set of U signature sequences that can be allocated to one or more receiver nodes in said wireless communication system.

17. The apparatus according to claim 15, wherein the processor is configured to obtain said second sequence of symbols {b_u,p(k)}, k=0, 1, . . . , L−

1 by;

multiplying, symbol-by-symbol, said first sequence of symbols {a_p(k)}, k=0, 1, . . . , L−

1 with a receiver specific signature sequence {s_u(k)}, k=0, 1, . . . , L−

1 so that b_u,p(k)=a_p(k)s_u(k), k=0, 1, . . . , L−

1, said receiver specific signature sequence {s_u(k)} being a u-th sequence from a set of U signature sequences that can be allocated to one or more receiver nodes in said wireless communication system.

18. The method according to claim 17, wherein said receiver specific signature sequence {s_u(k)} comprises elements having values +1 or −

1.

19. The method according to claim 17, wherein said receiver specific signature sequences {s_u(k)} are orthogonal to each other.

20. The apparatus according to claim 11, wherein the apparatus is a base station (eNB) or a relay node.