Base station, mobile station, reference signal transmission method, and channel quality measurement method

• US 10,356,644 B2
• Filed: 12/21/2017
• Issued: 07/16/2019
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Kakishima, Yuichi, Nagata, Satoshi, Kishiyama, Yoshihisa
• Primary Examiner(s): Zaidi, Iqbal
• Application Number:
  US15/850,808
• Publication Number:
  US 20180115919A1
• Time in Patent Office: 572 Days
• Field of Search: 370328-339, 455 82- 83, 375260-267
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• 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 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 72/1263 Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows

Abstract

A base station that communicates with a mobile station by using a plurality of antenna ports includes a mapping information communication unit configured to generate mapping of reference signals for measuring channel state information of the antenna ports. The base station applies identical mapping of the reference signals for measuring the channel state information to antenna ports included in any one group of the plurality of groups, while applying code division multiplexing to the reference signals for measuring the channel state information for the antenna ports. The base station applies different mappings of the reference signals for measuring the channel state information and communicates information indicating the generated mapping to the mobile station. The base station also includes a multiplexer to multiplex the reference signals in accordance with the generated mapping and a transmitter to transmit the reference signals for measuring the channel state information.

Claims

1. A base station for communicating with a mobile station using a plurality of antenna ports, a number of the plurality of antenna ports being greater than a predetermined number, the base station comprising:

a processor that;

generates mapping of reference signals for measuring channel state information for the plurality of antenna ports by dividing the plurality of antenna ports into a plurality of groups based on a reference antenna port number;

applies identical mapping of the reference signals for measuring the channel state information to antenna ports included in any one group of the plurality of groups, a number of the antenna ports included in the one group being the reference antenna port number, while applying code division multiplexing to the reference signals for measuring the channel state information for the antenna ports included in the one group;

applying applies different mappings of the reference signals for measuring the channel state information to the plurality of groups, respectively, and

communicates information indicating the generated mapping to the mobile station;

a multiplexer configured to multiplex the reference signals for measuring the channel state information in one or more resource elements in accordance with the generated mapping; and

a transmitter configured to transmit the reference signals for measuring the channel state information.

2. A mobile station for communicating with a base station including a plurality of antenna ports, a number of the plurality of antenna ports being greater than a predetermined number, the mobile station comprising:

a mapping information receiver configured to;

receive information indicating mapping of reference signals for measuring channel state information for the plurality of antenna ports, the mapping of the reference signals for measuring the channel state information for the plurality of antenna ports being generated by dividing the plurality of antenna ports into a plurality of groups based on a reference antenna port number;

applying identical mapping of the reference signals for measuring the channel state information to antenna ports included in any one group of the plurality of groups, a number of the antenna ports included in the one group being the reference antenna port number, while applying code division multiplexing to the reference signals for measuring the channel state information for the antenna ports included in the one group; and

applying different mappings of the reference signals for measuring the channel state information to the plurality of groups, respectively;

a processor that extracts the reference signals for measuring the channel state information based on the received information indicating the mapping;

a channel state information generator configured to generate the channel state information by using the extracted reference signals; and

a transmitter configured to transmit the generated channel state information.

3. A reference signal transmission method executed by a base station for communicating with a mobile station using a plurality of antenna ports, a number of the plurality of antenna ports being greater than a predetermined number, the method comprising:

generating mapping of reference signals for measuring channel state information for the plurality of antenna ports by dividing the plurality of antenna ports into a plurality of groups based on a reference antenna port number;

applying identical mapping of the reference signals for measuring the channel state information to antenna ports included in any one group of the plurality of groups, a number of the antenna ports included in the one group being the reference antenna port number, while applying code division multiplexing to the reference signals for measuring the channel state information for the antenna ports included in the one group;

applying different mappings of the reference signals for measuring the channel state information to the plurality of groups, respectively,

communicating information indicating the generated mapping to the mobile station;

multiplexing the reference signals for measuring the channel state information in one or more resource elements in accordance with the generated mapping; and

transmitting the reference signals for measuring the channel state information.

4. A channel quality measurement method executed by a mobile station for communicating with a base station including a plurality of antenna ports, a number of the plurality of antenna ports being greater than a predetermined number, the method comprising:

receiving information indicating mapping of reference signals for measuring channel state information for the plurality of antenna ports, the mapping of the reference signals for measuring the channel state information for the plurality of antenna ports being generated by dividing the plurality of antenna ports into a plurality of groups based on a reference antenna port number;

applying identical mapping of the reference signals for measuring the channel state information to antenna ports included in any one group of the plurality of groups, a number of the antenna ports included in the one group being the reference antenna port number, while applying code division multiplexing to the reference signals for measuring the channel state information for the antenna ports included in the one group;

applying different mappings of the reference signals for measuring the channel state information to the plurality of groups, respectively;

extracting the reference signals for measuring the channel state information based on the received information indicating the mapping; and

measuring the channel quality by using the extracted reference signals.