Methods and nodes in a wireless communication system

• US 10,164,751 B2
• Filed: 02/10/2015
• Issued: 12/25/2018
• Est. Priority Date: 08/10/2012
• 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: Berggren, Fredrik, Classon, Brian
• Primary Examiner(s): Wei, Siren
• Application Number:
  US14/618,573
• Publication Number:
  US 20150155993A1
• Time in Patent Office: 1,414 Days
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• 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

Abstract

Methods and nodes are provided for transmission of information, over at least one antenna port, in a subframe, which information is received by a receiver in a wireless communication system. Demodulation of the information entity by the receiver is enabled by also transmitting a Demodulation Reference Signal, DM-RS, comprising a DM-RS pattern, wherein positions in the DM-RS pattern are associated with at least one antenna port for transmission of the information entity. The method includes defining, for at least one subframe, a set of at least two distinct DM-RS patterns, assigning one DM-RS pattern, from the defined set of DM-RS patterns, to the receiver, and transmitting the information entity on the at least one antenna port associated with the assigned DM-RS pattern.

Claims

1. A method in a radio network node for transmission of an information entity, over at least one antenna port, in a subframe comprising a plurality of time-frequency resources, in which the information entity is to be received by a receiver in a wireless communication system, wherein demodulation of the information entity by the receiver is enabled by also transmitting a Demodulation Reference Signal (DM-RS) comprising a DM-RS pattern comprising a set of positions of the plurality of time-frequency resources, wherein the positions in the DM-RS pattern are associated with at least one antenna port for transmission of the information entity, the method comprising:

defining, for at least one subframe, a set of at least two distinct DM-RS patterns, the set of at least two distinct DM-RS patterns defined for at least one subframe comprises a first DM-RS pattern with a first reference signal density and a second DM-RS pattern with a second reference signal density, wherein the second reference signal density is higher than the first reference signal density, wherein the second DM-RS pattern is created by adding time-frequency resources, for DM-RS symbols to the first DM-RS pattern;

redefining antenna port mapping for the first DM-RS pattern, wherein redefining the antenna port mapping for the first DM-RS pattern further comprises assigning of the time-frequency resources of the second DM-RS to a smaller set of antenna ports of the first DM-RS pattern;

assigning one DM-RS pattern, from the defined set of DM-RS patterns, to the receiver; and

transmitting the information entity on the at least one antenna port associated with the assigned DM-RS pattern.

2. The method according to claim 1, wherein the assigned DM-RS pattern is receiver-specific, such that, for the at least one subframe, different DM-RS patterns are assignable to different receivers.

3. The method according to claim 1, wherein the assigned DM-RS pattern is cell-specific, such that, for the at least one subframe, the same DM-RS patterns are assignable to different receivers.

4. The method according to claim 3, wherein the assigned DM-RS pattern is cell-specific and determined by type of reference signals transmitted on a carrier.

5. The method according to claim 1, wherein different sets of DM-RS patterns are defined on different cells served by the radio network node, for a receiver in a multi carrier scenario such that a union of different sets of the different carriers comprises at least two distinct DM-RS patterns.

6. The method according to claim 1, wherein the DM-RS pattern is assigned to the receiver based on a predefined rule.

7. The method according to claim 1, wherein:

the wireless communication system is a Long Term Evolution (LTE) system;

the receiver is a User Equipment (UE); and

the radio network node is an evolved NodeB (eNodeB).

8. A radio network node, for transmission of an information entity, over at least one antenna port, in a subframe comprising a plurality of time-frequency resources, in which the information entity is to be received by a receiver in a wireless communication system, wherein demodulation of the information entity by the receiver is enabled by also transmitting a Demodulation Reference Signal (DM-RS), comprising a DM-RS pattern comprising a set of positions of said time-frequency resources assigned to the receiver, wherein the positions in the DM-RS pattern are associated with at least one antenna port for transmission of the information entity, wherein the radio network node comprises:

a processing circuit, configured for;

defining, for at least one subframe, a set of at least two distinct DM-RS patterns, the set of at least two distinct DM-RS patterns defined for at least one subframe comprises a first DM-RS pattern with a first reference signal density and a second DM-RS pattern with a second reference signal density, wherein the second reference signal density is higher than the first reference signal density, wherein the second DM-RS pattern is created by adding time-frequency resources, for DM-RS symbols to the first DM-RS pattern,

redefining antenna port mapping for the first DM-RS pattern, wherein redefining the antenna port mapping for the first DM-RS pattern further comprises assigning of the time-frequency resources of the second DM-RS to a smaller set of antenna ports of the first DM-RS pattern, and

assigning one DM-RS pattern, from the defined set of DM-RS patterns, to the receiver; and

a transmitting unit, configured for transmitting the information entity on the at least one antenna port associated with the assigned DM-RS pattern.