Multicode transmission using Walsh Hadamard transform
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorShiau-He Tsai
Life of this patent
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Abstract
A symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel is detected using Walsh Hadamard domain equalization techniques. The method comprises converting the received signal and the channel impulse response of the multipath channel from the time domain to the WHT domain, and determining the symbol sequence based on equalizing the received signal in the WHT domain using WHT spectra of the channel impulse response to remove inter-symbol interference from the received signal due to cross-correlation between Walsh codes.
Claims32
A method of detecting a symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel, the method comprising:
- calculating a transformation matrix that relates the Walsh Hadamard Transform (WHT) domain spectra of the data signal and the WHT domain spectra of the channel impulse response to the received signal;
- and
- estimating the symbol sequence as a function of the transformation matrix and the received signal.
A method of generating a Walsh code multiplexed signal for transmission in a wireless communication network comprising:
- generating the Walsh code multiplexed signal at a wireless communication transmitter;
- and
- inserting a cyclic prefix into the Walsh code multiplexed signal;
- and
- transmitting the Walsh code multiplexed signal from the wireless communication transmitter, after insertion of the cyclic prefix.
A receiver configured to detect a symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel, the receiver comprising one or more processing circuits configured to:
- calculate a transformation matrix that relates the Walsh Hadamard Transform (WHT) domain spectra of the data signal and the WHT domain spectra of the channel impulse response to the received signal;
- and
- estimate the symbol sequence as a function of the transformation matrix and the received signal.
A transmitter configured to generate a Walsh code multiplexed signal for transmission in a wireless communication network comprising:
- a coding circuit configured to generate a Walsh code multiplexed signal;
- and
- a prefix insertion circuit configured to insert a cyclic prefix into the Walsh code multiplexed signal for transmission of the Walsh code multiplexed signal.
A wireless communication transceiver for use in a wireless communication network, said wireless communication transceiver including a receiver circuit comprising one or more processing circuits configured to detect a symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and the channel impulse response, based on mitigating inter-path interference in the received signal by calculating a transformation matrix that relates the Walsh Hadamard Transform (WHT) domain spectra of the data signal and the WHT domain spectra of the channel impulse response to the received signal.
Dependencies are inferred from the claim text.