Spatial division multiplexing for MIMO devices
First Claim
1. A method of transmitting a signal from a transmitter in a communications system, comprising the steps of separating symbols of data to be transmitted into two categories, encoding the first category of symbols using an Alamouti encoding scheme, preparing the second category of symbols without Alamouti encoding, and transmitting all symbols using spatial transmission.
1 Assignment
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Accused Products
Abstract
A communications system, comprising a transmitter and a receiver, are operable to communicate information using a spatial multiplexing method. The transmitter is operable to separate data to be transmitted into two categories, Alamouti encoding the symbols of the first category and transmitting them on an even number of antennae, and not encoding the second category of symbols, but merely using a modulation scheme such as QAM, and transmitting them on one or more further antennae. A corresponding receiver is operable to successively detect signal components received on corresponding spatially displaced antennae, and then to determine an estimated channel response from the signal components. A weighting function is then derived to extract a stream of data from the received signal, which, on the basis that the Alamouti STBC encoded signal will have the highest signal to noise ratio, will normally be the latter, while other data not encoded according to Alamouti is detected thereafter.
14 Citations
54 Claims
- 1. A method of transmitting a signal from a transmitter in a communications system, comprising the steps of separating symbols of data to be transmitted into two categories, encoding the first category of symbols using an Alamouti encoding scheme, preparing the second category of symbols without Alamouti encoding, and transmitting all symbols using spatial transmission.
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16. A method of receiving a spatial division multiplexed signal comprising the steps of identifying at least two signal components received on spatially displaced antennae, then performing a data stream extraction step comprising:
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determining an estimated channel response from the signal components;
determining directly from the estimated channel response, a weighting function to apply to the received signal to extract a stream of data;
applying said weighting function so as to extract said stream; and
removing the effect of said stream of data from said received signal;
then repeating said data stream extraction step at least once so as to extract at least one further stream of data thereafter. - View Dependent Claims (17, 18, 19, 20, 23, 48)
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- 24. A transmitter for transmitting a signal comprising separating means for separating symbols of data to be transmitted into two categories, symbol encoding means for encoding the first category of symbols using an Alamouti encoding scheme, transmission preparation means for preparing the second category of symbols without Alamouti encoding, and transmitting means for transmitting all symbols using spatial transmission.
- 39. A receiver for receiving a spatial division multiplexed signal comprising component identifying means for identifying at least two signal components received on spatially displaced antennae, channel response determining means for determining an estimated channel response from the signal components, weighting function determining means for determining directly from the estimated channel response, a weighting function to apply to the received signal to extract a stream of data, stream extraction means for applying said weighting function so as to extract said stream and for removing the effect of said stream of data from said received signal, said weighting function determining means and said stream extraction means being operable to be applied repeatedly to said signal so as to extract at least one further stream of data thereafter.
Specification