Space-time coded transmissions within a wireless communication network
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 N t N r (L+1) in rich scattering environments, where N t (N r ) 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 N S blocks. The techniques may further include applying a permutation matrix to the N S blocks, generating a space-time block coded matrix having N t 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.
1. A method comprising:
parsing a stream of information-bearing symbols to form blocks of K symbols;
precoding the blocks of K symbols to form blocks having J symbols;
collecting consecutive N s blocks;
applying a permutation matrix to the N s blocks;
generating a space-time block coded matrix having N t rows, each row containing N D *J symbols;
generating N t transmission signals from the symbols of the N t rows; and
within N D block transmission time intervals, communicating the N t transmission signals through N t transmit antennas over a wireless communication medium.
2. The method of claim 1 , wherein J>K.
3. The method of claim 1 , wherein J=K.
4. The method of claim 1 , wherein N t =2 and N D =2, and applying the permutation matrix comprises applying the permutation matrix to generate the space-time block coded matrix as:
[
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 of J symbols, and s represents a symbol block.
5. The method of claim 4 , wherein the permutation matrix is drawn from a set of permutation matrices {P J (n) } n=0 J−1 .
6. The method of claim 4 , 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.
7. The method of claim 1 , wherein precoding the blocks of K symbols comprises adding a set of known symbols to each block of K symbols.
8. The method of claim 7 , wherein the set of known symbols comprises a preamble and a post-amble.
9. The method of claim 1 , 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 received 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.
10. The method of claim 9 , further comprising conjugating and applying a Fast Fourier Transform (FFT) to the blocks of the received symbols.
11. An apparatus comprising:
an encoder to apply a permutation matrix to N s blocks of J information-bearing symbols to form permutated blocks of symbols and to generate a space-time block coded matrix of the permutated blocks of symbols having N t rows, each row containing N D *J symbols;
a plurality of pulse shaping units to generate a plurality of transmission signals from the permutated blocks of symbols of the N t rows of the space-time block coded matrix; and
a plurality of antennae to communicate the transmission signals through a wireless communication medium within N D block transmission time intervals.
12. The apparatus of claim 11 , wherein the encoder collects consecutive N s blocks within a buffer.
13. The apparatus of claim 11 , wherein the apparatus parses a stream of symbols to form blocks of K symbols, the apparatus further comprising a precoder to precode the blocks of K symbols to form the blocks of J information-bearing symbols.
14. The apparatus of claim 13 , wherein the precoder adds a set of known symbols to each block of K symbols.
15. The apparatus of claim 14 , wherein the set of known symbols comprises a preamble and a post-amble.
16. The apparatus of claim 13 , wherein J>K.
17. The apparatus of claim 13 , wherein J=K.
18. The apparatus of claim 11 , wherein N t =2 and the encoder applies the permutation matrix to generate the space-time coded matrix as
[
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 of J symbols, and s represents a symbol block.
19. The apparatus of claim 18 , wherein the permutation matrix is drawn from a set of permutation matrices {P N (π)} π=0 J−1 .
20. The apparatus of claim 11 , wherein the apparatus comprises a base station within a wireless communication system.
21. The apparatus of claim 11 , 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.
22. A method comprising:
applying a permutation matrix to blocks of symbols of an outbound data stream of information bearing symbols to form permutated blocks of symbols;
generating a space-time block coded matrix of the permutated blocks of symbols having rows, each row containing symbols;
generating transmission signals from the permutated blocks of symbols of the rows of the space-time block coded matrix; and
communicating the transmission signals through a wireless communication medium within a number of transmission time intervals.
23. The method of claim 22 , wherein the space time block coded matrix has N t rows, and wherein N t represents a number of transmitters within a transmission device.
24. The method of claim 22 , further comprising:
parsing the outboard data stream of information-bearing symbols to form blocks of K symbols;
precoding the blocks of K symbols to form blocks having J symbols;
collecting consecutive N s blocks of the J symbols;
generating the space-time block coded matrix to have N t rows and N D *J symbols per row, wherein N D represents the number of transmission time intervals for communicating the transmission signals.