System and method for multiple input multiple output wireless transmission
AssigneeEricsson Inc.
InventorsJianming Wu, Wen Tong, Mo-Han Fong
Life of this patent
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Abstract
Systems and methods for MIMO wireless transmission are provided. At the transmitter, a plurality of encoded packets are modulated, and the symbols are divided between several transmit antennas. The transmitter spreads some of the symbols of each packet using a respective subset of an available Walsh code space. A given transmit antenna then transmits part of each packet spread by the respective subset. In some implementations, this achieves the benefits of the PARC system, and at the same time achieves part of the benefits of the STTD system. Advantageously, only a single reverse link control channel is required if adaptive coding and modulation is to be performed.
Claims15
A method of transmitting a first set of modulation symbols of a first encoded packet comprising:
- spreading a first subset of the first set of modulation symbols using a first subset of an orthogonal code set to generate a first spread signal, and transmitting the first spread signal on a first antenna such that each modulation symbol of the first subset of modulation symbols is spread with a respective distinct orthogonal code from the first subset of the orthogonal code set;
- spreading a second subset of the first set of modulation symbols using a second subset of the orthogonal code set to generate a second spread signal and transmitting the second spread signal on a second antenna such that each modulation symbol of the second subset of modulation symbols is spread with a respective distinct orthogonal code from the second subset of the orthogonal code set;
- the first subset of the first set of modulation symbols comprising at least two modulation symbols;
- and
- the second subset of the first set of modulation symbols comprising at least two modulation symbols.
A method comprising:
- defining M disjoint subsets of an orthogonal code set, where M≧2 is a number of transmit antennas;
- for each of a plurality M sets of modulation symbols, each set associated with a respective encoded packet:
- a) defining M subsets of the set of modulation symbols;
- b) spreading each of the M subsets using a respective one of the M disjoint subsets to produce a respective spread signal component;
- for each antenna, generating a respective spread signal for the transmit antenna by combining together M spread signal components, the M spread signal components combined for the antenna including one of the spread signal components produced for each set of the M sets of modulation symbols, each of the M spread signal components combined for the antenna using a different one of the M disjoint subsets of the orthogonal code set;
- for each antenna, transmitting the respective spread signal;
- wherein the spread signals collectively include all of the spread signal components.
A system comprising:
- a) a transmitter comprising:
- M transmit antennas;
- signal spreading functions which for each of the plurality M of transmit antennas where M>=2, generate respective spread signal by:
- defining M disjoint subsets of an orthogonal code set;
- for each of a plurality of M sets of modulation symbols, each set associated with a respective encoded packet:
- i) defining M subsets of the set of modulation symbols;
- ii) spreading each of the M subsets using a respective one of the M disjoint subsets to produce a respective spread signal component;
- for each antenna, generating the respective spread signal for the transmit antenna by combining together M spread signal components, the M spread signal components combined for the antenna including one of the spread signal components produced for each set of the M sets of modulation symbols, each of the M spread signal components combined for the antenna using a different one of the M disjoint subsets of the orthogonal code set;
- for each antenna, transmitting the respective spread signal;
- wherein the spread signals collectively include all of the spread signal components;
- b) at least two receivers each comprising at least two receive antennas, each receiver being adapted to perform decoding and modulation of signals received from the transmitter to recover at least one respective packet.
Dependencies are inferred from the claim text.