Training-based channel estimation for multiple-antennas

A space-time diversity transmitter that includes (a) n transmitting antennas, where n is greater than one, (b) an encoder of an applied information bit stream, said encoder developing n symbol streams, and (c) a constellation mapper responsive to said n symbol streams, for mapping symbols of each of said n symbol streams into a standard signal constellation to create a mapped stream, said constellation mapper applying each of the created n mapped stream to a different one of said n antennas, the improvement comprising:

• a generator of a symbols sequence;
• an encoder for creating n training sequences from said symbols sequence;
• and a training sequence mapper that maps said n training sequences onto a standard constellation to develop n mapped training sequences, and applies the n mapped training sequences to said n antennas at times when said constellation mapper stops applying said n mapped stream to said n antennas;
• where said constellation mapper and said training sequence mapper are one and the same.

A space-time diversity transmitter that includes (a) n transmitting antennas, where n is greater than one, (b) an encoder of an applied information bit stream, said encoder developing n symbol streams, and (c) a constellation mapper responsive to said n symbol streams, for mapping symbols of each of said n symbol streams into a standard signal constellation to create a mapped stream, said constellation mapper applying each of the created n mapped stream to a different one of said n antennas, the improvement comprising:

• a generator of a symbols sequence;
• an encoder for creating n training sequences from said symbols sequence;
• and a training sequence mapper that maps said n training sequences onto a standard constellation to develop n mapped training sequences, and applies the n mapped training sequences to said n antennas at times when said constellation mapper stops applying said n mapped stream to said n antennas;
• where said constellation mapper also serves as said training sequence mapper.

A space-time diversity transmitter that includes n transmitting antennas, where n is greater than one, comprising:

• a generator of training sequences;
• and
• an encoder, responsive to signals created by said generator, for developing n sequences that are applied to said n antennas, each sequence having n intervals, said sequences being characterized by matrix
• U
• =
• [
• u
• 11
• u
• 12
• …
• u
• 1
• ⁢
• n
• u
• 21
• u
• 22
• …
• u
• 2
• ⁢
• n
• ⋮
• ⋮
• ⋱
• ⋮
• u
• n1
• u
• n2
• …
• u
• nn
• ]
• such that UUH=KI, where UH is the Hermetian of U, K is a constant, and I is the identity matrix, and uij is a convolution matrix of sequence applied to antenna j at interval i.

A receiver comprising an antenna, a channel estimator responsive to signals received from said antenna, and a detector response to signals received from said antenna and to signal applied by said channel estimator, the improvement comprising:

• said channel estimator is constructed (a) to receive from said antenna signal y1 during a first period of Nt/2 symbol periods, where Nt is a predetermined constant, and signal y2 during a second period of Nt/2 symbol periods, (b) to develop matrix product
• [
• r
• 1
• r
• 2
• ]
• =
• [
• -
• S
• H
• S
• H
• S
• H
• S
• H
• ]
• ⁢
• [
• y
• 1
• y
• 2
• ]
• ,
• where S is a predetermined matrix, and SH is the Hermitian of S, (c) to develop vector signal
• h
• 1
• =
• 1
• K
• ⁢
• r
• 1
• and vector signal
• h
• 2
• =
• 1
• K
• ⁢
• r
• 2
• ,
• where K is a
• predetermined constant and r1 and r2 are the receiver processed signals, and (d) to apply vector signals h1 and h2 to said detector.

A receiver comprising an antenna, a channel estimator responsive to signals received from said antenna, and a detector response to signals received from said antenna and to signal applied by said channel estimator, the improvement comprising:

• said channel estimator receives signals from a transmitter having n transmitting antennas, develops therefrom received signal vectors y1 and y2, from two sets of received symbol periods, develops
• [
• h
• eq
• even
• h
• eq
• odd
• ]
• =
• KS
• H
• ⁡
• [
• y
• 1
• y
• 2
• ]
• ,
• where K is a preselected constant, heveneq is the estimate of the transfer function determined from even constellation symbols, hoddeq is the estimate of the transfer function determined from odd constellation symbols, and SH is a preselected matrix, and develops estimate signal
• h
• 1
• =
• h
• eq
• even
• +
• h
• eq
• odd
• 2
• that is applied to said detector, and estimate signal
• h
• 2
• =
• h
• eq
• even
• -
• h
• eq
• odd
• 2
• that is applied to said detector.