# US 7,609,782 B2 · Space-time coded transmissions within a wireless communication network

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- Number: US 7,609,782 B2
- Document ID: US7609782B2
- Status: Granted
- Kind: B2
- Application number: 11/682,664
- Filed: 2007-03-06
- Published: 2008-02-14
- Granted: 2009-10-27
- Earliest claimed: 2001-05-25
- Assignees: Regents of the University of Minnesota
- Inventors: Georgios B. Giannakis; Shengli Zhou
- Web page: https://patentgrep.com/patent/US7609782B2

## CPC

- H04L 27/2607: {Cyclic extensions}
- H04L 1/0618: {Space-time coding}
- H04L 5/0023: {Time-frequency-space}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Techniques are described for space-time block coding for single-carrier block transmissions over frequency selective multipath fading channels. Techniques are described that achieve a maximum diversity of order NtNr (L+1) in rich scattering environments, where Nt (Nr) is the number of transmit (receive) antennas, and L is the order of the finite impulse response (FIR) channels. The techniques may include parsing a stream of information-bearing symbols to form blocks of K symbols, precoding the symbols to form blocks having J symbols, and collecting consecutive Ns blocks. The techniques may further include applying a permutation matrix to the Ns blocks, generating a space-time block coded matrix having Nt rows that are communicated through a wireless communication medium. The receiver complexity is comparable to single antenna transmissions, and the exact Viterbi's algorithm can be applied for maximum-likelihood (ML) optimal decoding.

## Claims

### Claim 1

A method comprising:
applying, in a transmitting device, a permutation matrix to blocks of symbols of an outbound data stream to permute the blocks of the symbols, wherein the permutation matrix is selected from a plurality of permutation matrices as a function of a symbol index of the outbound data stream, and wherein the selected permutation matrix applies a reverse cyclic shift to the symbols as a function of the symbol index;
generating a space-time block coded matrix from the permuted blocks of the symbols;
generating transmission signals from the space-time block coded matrix; and
communicating the transmission signals through a wireless communication medium.

### Claim 2 (depends on 1)

The method of claim 1, wherein the space-time block coded matrix has Nt rows, wherein Nt represents a number of transmitters within a transmission device.

### Claim 3 (depends on 2)

The method of claim 2, further comprising:
parsing the outbound data stream of symbols to form blocks of K symbols;
precoding the blocks of K symbols to form blocks having J symbols;
collecting consecutive Ns blocks; and
generating the space-time block coded matrix to have Nt rows and ND*J symbols per row, wherein ND represents a number of transmission time intervals for communicating the transmission signals.

### Claim 4 (depends on 3)

The method of claim 3, further comprising inserting a cyclic prefix for each of the permuted blocks of the symbols prior to generating the transmission signals, wherein the cyclic prefix has a length selected as a function of a channel order of the wireless communication medium.

### Claim 5 (depends on 3)

The method of claim 3, wherein J>K.

### Claim 6 (depends on 3)

The method of claim 3, wherein J=K.

### Claim 7 (depends on 3)

The method of claim 3, wherein Nt=2 and ND=2, and applying the permutation matrix comprises applying the permutation matrix to generate the space-time block coded matrix:
[
s
⁡
(
2
⁢
i
)
-
P
⁢
⁢
s
*
⁡
(
2
⁢
i
+
1
)
s
⁡
(
2
⁢
i
+
1
)
P
⁢
⁢
s
*
⁡
(
2
⁢
i
)
]
,
where P represents the permutation matrix, i represents an index into the blocks having J symbols, and s represents a symbol block.

### Claim 8 (depends on 7)

The method of claim 7, wherein the permutation matrix is drawn from a set of permutation matrices {Pjn}n=0j−1.

### Claim 9 (depends on 7)

The method of claim 7, wherein each row of a second column of the space-time block coded matrix stores a block that is a conjugated and permuted version of a corresponding block from another row of a first column.

### Claim 10 (depends on 3)

The method of claim 3, wherein precoding the blocks of K symbols comprises adding a set of known symbols to each block of K symbols.

### Claim 11 (depends on 10)

The method of claim 10, wherein the set of known symbols comprises a preamble and a post-amble.

### Claim 12 (depends on 3)

The method of claim 3, further comprising:
receiving a signal from the wireless communication medium, wherein the signal comprises a stream of received symbols;
parsing the received symbols of the signal to form blocks of J symbols;
applying the permutation matrix to the blocks of the received symbols to form permutated blocks; and
separately demodulating transmitted data from the permutated blocks of the received symbols.

### Claim 13 (depends on 12)

The method of claim 12, further comprising conjugating and applying a Fast Fourier Transform (FFT) to the permutated blocks of the received symbols.

### Claim 14

An apparatus comprising:
an encoder to apply a permutation matrix to blocks of information-bearing symbols to form permutated blocks of symbols and to generate a space-time block coded matrix of the permutated blocks of symbols, wherein the permutation matrix applies a reverse cyclic shift to the information-bearing symbols, wherein the encoder is configured to select the permutation matrix from a plurality of permutation matrices as a function of a symbol index, and to apply the selected permutation matrix to perform a reverse cyclic shift as a function of the symbol index;
a plurality of pulse shaping units to generate a plurality of transmission signals from the permutated blocks of symbols of the space-time block coded matrix; and
a plurality of antennae to communicate the transmission signals through a wireless communication medium.

### Claim 15 (depends on 14)

The apparatus of claim 14, wherein the encoder is adapted to collect consecutive N, blocks within a buffer prior for application of the permutation matrix to the Ns blocks, and to form the space-time block coded matrix having Nt rows of symbols.

### Claim 16 (depends on 15)

The apparatus of claim 15, wherein Nt=2 and the encoder is adapted to apply the permutation matrix to generate the space-time block coded matrix according to the following equation:
[
s
⁡
(
2
⁢
i
)
-
Ps
*
⁡
(
2
⁢
i
+
1
)
s
⁡
(
2
⁢
i
+
1
)
Ps
*
⁡
(
2
⁢
i
)
]
,
where P represents the permutation matrix, i represents an index, and s represents a symbol block.

### Claim 17 (depends on 16)

The apparatus of claim 16, wherein the permutation matrix is drawn from a set of permutation matrices {Pjn}n=0j−1.

### Claim 18 (depends on 14)

The apparatus of claim 14, further comprising a precoder to precode the information-bearing symbols to form blocks having J symbols, wherein each row of the space-time block coded matrix contains ND*J symbols, wherein ND represents a number of block transmission time intervals for transmitting the space-time block coded matrix.

### Claim 19 (depends on 18)

The apparatus of claim 18, wherein the precoder is adapted to add a set of known symbols to each block of K symbols.

### Claim 20 (depends on 19)

The apparatus of claim 19, wherein the set of known symbols comprises a preamble and a post amble.

### Claim 21 (depends on 19)

The apparatus of claim 19, wherein J>K.

### Claim 22 (depends on 19)

The apparatus of claim 19, wherein J=K.

### Claim 23 (depends on 14)

The apparatus of claim 14, wherein the apparatus comprises a base station within a wireless communication system.

### Claim 24 (depends on 14)

The apparatus of claim 14, wherein the apparatus comprises one of a cellular phone, a personal digital assistant, a laptop computer, a desktop computer, and a two-way communication device.

### Claim 25 (depends on 14)

The apparatus of claim 14, wherein the apparatus is adapted to select a cyclic prefix as a length selected as a function of a channel order of the wireless communication medium.