Channel estimation in a wireless communication system

A user equipment for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, each midamble being a shifted version of a basic midamble code having a period of P, a maximum number of midamble shifts being K, the user equipment comprising:

• means for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• means for constructing a P by P square circulant matrix including the K midamble shifts;
• and
• means for determining a channel response for each of the K midamble shifts using a prime factor algorithm (PFA) discrete Fourier transform (DFT) algorithm, the received combined signal and the P by P square circulant matrix, the PFA DFT algorithm having a plurality of stages, each stage having P inputs.

A user equipment for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, each midamble being a shifted version of a basic midamble code having a period of P, a maximum number of midamble shifts being K, the user equipment comprising:

• an antenna for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• and
• a Steiner algorithm block for constructing a P by P square circulant matrix including the K midamble shifts;
• and for determining a channel response for each of the K midamble shifts using a prime factor algorithm (PFA) discrete Fourier transform (DFT) algorithm, the received combined signal and the P by P square circulant matrix, the PFA DFT algorithm having a plurality of stages, each stage having P inputs.

A base station for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, each midamble being a shifted version of a basic midamble code having a period of P, a maximum number of midamble shifts being K, the base station comprising:

• means for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• means for constructing a P by P square circulant matrix including the K midamble shifts;
• and
• means for determining a channel response for each of the K midamble shifts using a prime factor algorithm (PFA) discrete Fourier transform (DFT) algorithm, the received combined signal and the P by P square circulant matrix, the PFA DFT algorithm having a plurality of stages, each stage having P inputs.

A base station for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, each midamble being a shifted version of a basic midamble code having a period of P, a maximum number of midamble shifts being K, the base station comprising:

• an antenna for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• and
• a Steiner algorithm block for constructing a P by P square circulant matrix including the K midamble shifts;
• and for determining a channel response for each of the K midamble shifts using a prime factor algorithm (PFA) discrete Fourier transform (DFT) algorithm, the received combined signal and the P by P square circulant matrix, the PFA DFT algorithm having a plurality of stages, each stage having P inputs.

A method for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access communication system, each burst having an assigned midamble, the method comprising:

• receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• processing the received combined signal with a Steiner based algorithm to produce initial channel estimates;
• estimating noise of the received combined signal using the initial channel estimates;
• eliminating samples of the initial channel estimates not exceeding a first threshold producing processed channel estimates;
• detecting received midambles using the processed channel estimates;
• and
• using the detected midambles, processing the processed channel estimates to produce a channel estimate for each detected midamble, the processing the processed channel estimates including eliminating samples of the processed channel estimates not exceeding a second threshold.

A user equipment for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, the user equipment comprising:

• means for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• first means for processing the received combined signal with a Steiner based algorithm to produce initial channel estimates;
• means for estimating noise of the received combined signal using the initial channel estimates;
• means for eliminating samples of the initial channel estimates not exceeding a first threshold producing processed channel estimates;
• means for detecting received midambles using the processed channel estimates;
• and
• second means using the detected midambles, for processing the processed channel estimates to produce a channel estimate for each detected midamble, the processing means eliminating samples of the processed channel estimates not exceeding a second threshold.

A user equipment for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, the user equipment comprising:

• an antenna for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• a Steiner algorithm block for processing the received combined signal with a Steiner based algorithm to produce initial channel estimates;
• a noise estimator for estimating noise of the received combined signal using the initial channel estimates;
• a first post processor for eliminating samples of the initial channel estimates not exceeding a first threshold producing processed channel estimates;
• a midamble detection device for detecting received midambles using the processed channel estimates;
• and
• a second post processor using the detected midambles, for processing the processed channel estimates to produce a channel estimate for each detected midamble, the second post processor including eliminating samples of the processed channel estimates not exceeding a second threshold.

A base station for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, the base station comprising:

• means for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• first means for processing the received combined signal with a Steiner based algorithm to produce initial channel estimates;
• means for estimating noise of the received combined signal using the initial channel estimates;
• means for eliminating samples of the initial channel estimates not exceeding a first threshold producing processed channel estimates;
• means for detecting received midambles using the processed channel estimates;
• and
• second means using the detected midambles, for processing the processed channel estimates to produce a channel estimate for each detected midamble, the second means eliminating samples of the processed channel estimates not exceeding a second threshold.

A base station for estimating a channel experienced by a plurality of communication bursts transmitted substantially simultaneously in a time slot of a time division duplex/code division multiple access format, each burst having an assigned midamble, the base station comprising:

• an antenna for receiving a combined signal, the combined signal including a received version of each of the communication burst's midambles;
• a Steiner algorithm block for processing the received combined signal with a Steiner based algorithm to produce initial channel estimates;
• a noise estimator for estimating noise of the received combined signal using the initial channel estimates;
• a first post processor for eliminating samples of the initial channel estimates not exceeding a first threshold producing processed channel estimates;
• a midamble detection device for detecting received midambles using the processed channel estimates;
• and
• a second post processor using the detected midambles, for processing the processed channel estimates to produce a channel estimate for each detected midamble, the second post processor eliminating samples of the processed channel estimates not exceeding a second threshold.