Method and base station for transmitting reference signals, and method and user equipment for receiving reference signals

A method for receiving a plurality of reference signals (RSs) at a user equipment (UE) from a base station (BS) in a wireless communication system, the method comprising:

• receiving, by the UE from the BS, the plurality of RSs, the received plurality of RSs having been multiplexed by the BS in each of a first code division multiplexing (CDM) group and a second CDM group,
• wherein RS0, RS1, RS4 and RS 6 among the plurality of RSs are multiplexed on a subcarrier of the first CDM group, hereinafter referred to as a first subcarrier, according to (RS0 RS1 RS4 RS6)×(a b c d), and RS2, RS3, RS5 and RS7 among the plurality of RSs are multiplexed on a subcarrier of the second CDM group, hereinafter referred to as a second subcarrier, which is adjacent to the first subcarrier, according to (RS2 RS3 RS5 RS7)×(c d a b), and
• wherein the a, b, c and d are orthogonal sequences defined as
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A base station (BS) for transmitting a plurality of reference signals (RSs) to a user equipment (UE) in a wireless communication system, the BS comprising:

• a transmitter;
• and
• a processor, operatively coupled to the transmitter, configured to control the transmitter,
• wherein the processor is configured to multiplex the plurality of RSs with spreading orthogonal sequences on each of a first code division multiplexing (CDM) group and a second CDM group and control the transmitter to transmit the multiplexed plurality of RSs to the UE,
• wherein RS0, RS1, RS4 and RS 6 among the plurality of RSs are multiplexed on a subcarrier of the first CDM group, hereinafter referred to as a first subcarrier, according to (RS0 RS1 RS4 RS6)×(a b c d), and RS2, RS3, RS5 and RS7 among the plurality of RSs are multiplexed on a subcarrier of the second CDM group, hereinafter referred to as a second subcarrier, which is adjacent to the first subcarrier, according to (RS2 RS3 RS5 RS7)×(c d a b), and
• wherein the a, b, c and d are orthogonal sequences defined as
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A user equipment (UE) for receiving a plurality of reference signals (RSs) from a base station (BS) in a wireless communication system, the UE comprising:

• a receiver;
• and
• a processor, operatively coupled to the receiver, configured to control the receiver,
• wherein the processor is configured to control the receiver to receive the plurality of RSs from the BS, the received plurality of RSs having been multiplexed by the BS in each a first code division multiplexing (CDM) group and a second CDM group,
• wherein RS0, RS1, RS4 and RS 6 among the plurality of RSs are multiplexed on a subcarrier of the first CDM group, hereinafter referred to as a first subcarrier, according to (RS0 RS1 RS4 RS6)×(a b c d), and RS2, RS3, RS5 and RS7 among the plurality of RSs are multiplexed on a subcarrier of the second CDM group, hereinafter referred to as a second subcarrier, which is adjacent to the first subcarrier, according to (RS2 RS3 RS5 RS7)×(c d a b),
• wherein the a, b, c and d are orthogonal sequences defined as
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• .