Multiple-antenna system for cell-specific and user-specific transmission
A reception method and apparatus for use in a multi-cell orthogonal frequency division multiple access (OFDMA) wireless system. In a unicast receive mode during a first receive time period, a first group of orthogonal frequency division multiplexing (OFDM) symbols is received by a mobile device from multiple of a plurality of antennas at a serving base station. In a single-frequency-network (SFN) receive mode during a second receive time period, a second group of OFDM symbols is received by the mobile device from one of a plurality of antennas at the serving base station. The transition between the first receive time period and the second receive time period occurs during a cyclic prefix or a cyclic postfix between OFDM symbols, and the plurality of antennas produce a first beam pattern during the unicast receive mode and a second beam pattern during the SFN receive mode.
1 . A method performed by an apparatus for wireless transmission, the method comprising:
transmitting control information associated with an orthogonal frequency division multiple access (OFDMA) transmission; and
transmitting the OFDMA transmission including at least a first beam pattern that carries first unicast data and a second beam pattern that carries second unicast data that is transmitted at least in-part simultaneously with the first unicast data, wherein the OFDMA transmission is formed by:
allocating a first set of subcarriers to a first recipient device and a second set of subcarriers to a second recipient device, wherein the first set of subcarriers includes first user-specific data subcarriers and first pilot subcarriers and the second set of subcarriers includes second user-specific data subcarriers and second pilot subcarriers; and
applying a first set of complex weights to the first set of subcarriers to form the first beam pattern and applying a second set of complex weights to the second set of subcarriers to form the second beam pattern.
2 . The method of claim 1 , wherein the control information includes downlink resource allocation information indicating the first set of subcarriers and the second set of subcarriers.
3 . The method of claim 1 , wherein the control information allocates first groups of subcarriers to the first recipient device and allocates second groups of subcarriers to the second recipient device.
4 . The method of claim 3 , wherein the control information includes a preamble.
5 . The method of claim 4 , wherein the preamble is decodable by the first recipient device and the second recipient device.
6 . The method of claim 1 , further comprising transmitting a mid-amble.
7 . The method of claim 1 , wherein applying the first set of complex weights includes:
applying a complex weight per subcarrier; or
applying a subset of complex weights per a group of multiple subcarriers.
8 . The method of claim 1 , wherein the first beam pattern is directionally different in azimuth than the second beam pattern.
9 . The method of claim 1 , wherein the first beam pattern is directionally different in elevation than the second beam pattern.
10 . The method of claim 1 , wherein the OFDMA transmission is based on modulation and coding using link adaptation.
11 . The method of claim 1 , wherein a more robust modulation and coding is used for the control information than used for the first unicast data and used for the second unicast data.
12 . The method of claim 1 , wherein the transmitting the OFDMA transmission further includes forward error correction encoding, interleaving, modulation, and mapping modulated data to subcarriers.
13 . The method of claim 1 , wherein the transmitting the OFDMA transmission further includes:
performing an inverse transform on the first set of subcarriers and the second set of subcarriers to generate time domain orthogonal frequency divisional multiplexing (OFDM) symbols;
adding cyclic prefixes onto the time domain OFDM symbols; and
transmitting the time domain OFDM symbols and cyclic prefixes via a plurality of antennas.
14 . The method of claim 1 , wherein the transmitting the OFDMA transmission includes transmitting at least a portion of the first unicast data and at least a portion of the second unicast data in a same orthogonal frequency division (OFDM) symbol that includes both the first set of subcarriers and the second set of subcarriers.
15 . The method of claim 1 , wherein the unicast data includes a frame control field.
16 . An apparatus comprising:
a controller and a transmitter;
wherein the controller and the transmitter are collectively configured to:
transmit control information associated with an orthogonal frequency division multiple access (OFDMA) transmission; and
transmit the OFDMA transmission including at least a first beam pattern that carries first unicast data and a second beam pattern that carries second unicast data that is transmitted at least in-part simultaneously with the first unicast data, wherein the OFDMA transmission is formed by:
allocating a first set of subcarriers to a first recipient device and a second set of subcarriers to a second recipient device, wherein the first set of subcarriers includes first user-specific data subcarriers and first pilot subcarriers and the second set of subcarriers includes second user-specific data subcarriers and second pilot subcarriers; and
applying a first set of complex weights to the first set of subcarriers to form the first beam pattern and applying a second set of complex weights to the second set of subcarriers to form the second beam pattern.
17 . The apparatus of claim 16 , wherein the control information allocates first groups of subcarriers to the first recipient device and allocates second groups of subcarriers to the second recipient device, and wherein the control information includes a preamble that is decodable by the first recipient device and the second recipient device.
18 . The apparatus of claim 16 , wherein:
a complex weight is applied per subcarrier; or
a subset of complex weights is applied per a group of multiple subcarriers.
19 . The apparatus of claim 16 , further comprising a plurality of antennas, wherein the controller and the transmitter are further collectively configured to:
perform an inverse transform on the first set of subcarriers and the second set of subcarriers to generate time domain orthogonal frequency divisional multiplexing (OFDM) symbols;
add cyclic prefixes onto the time domain OFDM symbols; and
transmit the time domain OFDM symbols and cyclic prefixes via the plurality of antennas.
20 . The apparatus of claim 16 , wherein the controller and the transmitter are further collectively configured to transmit at least a portion of the first unicast data and at least a portion of the second unicast data in a same orthogonal frequency division (OFDM) symbol that includes both the first set of subcarriers and the second set of subcarriers.