High diversity time-space coding and decoding for MIMO systems
First Claim
1. A method of wireless transmission, the method comprising:
- receiving a plurality of antenna symbols via a plurality of pairs of transmission streams, wherein a pair of transmission streams represents a single pair of symbols at a given time, such that during a first time period each of said pairs of transmission streams includes a first pair of symbols and wherein during a second time period, each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols previously included in that stream;
generating an output corresponding to said at least two pairs of symbols by multiplying a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and
generating said output based on a product of said multiplying.
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Accused Products
Abstract
A diversity transmission scheme uses a number of antennas that is greater than the limitation of two transmitting antennas in the well-known Alamouti scheme. In an embodiment comprising four antennas, the antennas transmit in pairs such that each antenna transmits a block that is used in the Alamouti scheme. This increases the transmission rate. For example, the transmission of two signals at a given time slot increases transmission rate by a factor of two. The invention not only increases the number of antennas, but also increases the transmission rate. At the receiver end, the code is decoded without matrix inversion and without much noise enhancement. Moreover, noise enhancement stability is increased by a simple, partial interference cancellation scheme, that results in improved decoding performance.
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Citations
19 Claims
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1. A method of wireless transmission, the method comprising:
receiving a plurality of antenna symbols via a plurality of pairs of transmission streams, wherein a pair of transmission streams represents a single pair of symbols at a given time, such that during a first time period each of said pairs of transmission streams includes a first pair of symbols and wherein during a second time period, each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols previously included in that stream;
generating an output corresponding to said at least two pairs of symbols by multiplying a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and
generating said output based on a product of said multiplying.- View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A wireless receiver to receive a plurality of antennas symbols via a plurality of pairs of transmission streams representing a plurality of different pairs of symbols, and to generate an output corresponding to said at least two pairs of symbols, wherein during a first time period each of said pairs of transmission streams includes a first pair of symbols, and wherein during a second time period each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols;
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wherein said receiver is further adapted to multiply a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and
to generate said output based on a product of said multiplying. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A multiple-input-multiple-output wireless transmission system comprising:
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a wireless transmitter to transmit a plurality of pairs of wireless transmission streams via a plurality of transmit antennas, said plurality of pairs of transmission streams representing a plurality of different pairs of symbols, wherein during a first time period each of said pairs of transmission streams includes a first pair of symbols, and wherein during a second time period each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols;
a receiver to receive via a plurality of receive antennas symbols of the plurality of pairs of transmission streams, to generate an output corresponding to said at least two pairs of symbols; andto multiply a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and
to generate said output based on a product of said multiplying. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification