Cell-specific shifting of reference signals in multi-stream transmissions

A subscriber station comprising:

• a downlink receive path comprising circuitry configured to receive a plurality of reference signals in one or more subframes, each subframe comprising one or more resource blocks, each resource block comprising S Orthogonal Frequency Division Multiplexing (OFDM) symbols, each of the S OFDM symbols comprising N subcarriers, and each subcarrier of each OFDM symbol comprises a resource element;
• and
• a reference signal receiver configured to receive the plurality of reference signals allocated to selected resource elements of a resource block,
• wherein, prior to reception by the subscriber station, the plurality of reference signals are circularly shifted in a time domain of the resource block by an hshift value that is based at least partly upon a cell_ID of a base station.

A base station comprising:

• a downlink transmit path comprising circuitry configured to transmit a plurality of reference signals in one or more subframes, each subframe comprising one or more resource blocks, each resource block comprising S Orthogonal Frequency Division Multiplexing (OFDM) symbols, each of the S OFDM symbols comprising N subcarriers, and each subcarrier of each OFDM symbol comprises a resource element;
• and
• a reference signal allocator configured to:
• allocate the plurality of reference signals to selected resource elements of a resource block,
• group the selected resource elements into one or more sub-groups, wherein each of the one or more sub-groups has two or more contiguous resource elements in a frequency domain, and wherein each of the one or more sub-groups has a same m number of resource elements, and
• circularly shift each of the one or more sub-groups of resource elements in the frequency domain by a vshift value, the vshift value being an integer multiple of the m number of resource elements in each of the one or more sub-groups.

A subscriber station comprising:

• a downlink receive path comprising circuitry configured to receive a plurality of reference signals in one or more subframes, each subframe comprising one or more resource blocks, each resource block comprising S Orthogonal Frequency Division Multiplexing (OFDM) symbols, each of the S OFDM symbols comprising N subcarriers, and each subcarrier of each OFDM symbol comprises a resource element;
• and
• a reference signal receiver configured to receive the plurality of reference signals allocated to selected resource elements of a resource block,
• wherein, prior to reception by the subscriber station,:
• the selected resource elements are grouped into one or more sub-groups, wherein each of the one or more sub-groups has two or more contiguous resource elements in a frequency domain, and wherein each of the one or more sub-groups has a same m number of resource elements, and
• each of the one or more sub-groups of resource elements are circularly shifted in the frequency domain by a vshift value, the vshift value being an integer multiple of the m number of resource elements in each of the one or more sub-groups.