Multiple transmit antenna interleaver design
View Patent ↗An arrangement of interleavers allocates bits from an input symbol across sub-symbols transmitted via sub-carriers of multiple orthogonal frequency division multiplex (OFDM) carriers. The input bits are allocated in a fashion to provide separation across subcarriers, and rotation of sub-symbols across the OFDM carriers provides additional robustness in the present of signal path impairments.
1. A wireless device comprising:
a wireless interface; and
processing circuitry, the wireless interface and the processing circuitry operable to process bits of an input symbol to form N orthogonal frequency division multiplex (OFDM) transmit streams across K subcarriers, wherein at least one input symbol comprises KN subsymbols, wherein at least one of the KN subsymbols comprises B bits of the input symbol and wherein each subsymbol is communicated via an associated subcarrier of the N transmit streams by:
interleaving the bits of the input symbol by at least one permutation to form permutated bits;
grouping permutated bits into subsymbols;
grouping the subsymbols into blocks of subsymbols; and
rotating the blocks of subsymbols between the N OFDM transmit streams, wherein N is greater than 1.
2. The wireless device of claim 1 , wherein the wireless interface and processing circuitry are further operable to allocate bits of an input symbol to OFDM transmit streams in a mode selected from a plurality of modes.
3. The wireless device of claim 1 , wherein the wireless interface and processing circuitry are further operable to map bit k of the input symbol to bit i of a first bit sequence according to the formula:
i
=
B
K
N
r
(
k
mod
r
)
+
⌊
k
r
⌋
k
=
0
,
1
,
…
,
B
K
N
-
1
wherein r denotes interleaving depth; and
wherein
⌊
k
r
⌋
denotes the largest integer not exceeding the value
k
r
.
4. The wireless device of claim 3 , wherein the wireless interface and processing circuitry are further operable to map bit i of the first bit sequence to bit j of a second bit sequence according to the formula:
j
=
s
⌊
i
s
⌋
+
mod
(
i
+
B
K
N
-
⌊
ri
B
K
N
⌋
,
s
)
i
=
0
,
1
,
…
,
B
K
N
-
1
wherein s=max(B/2,1); and
wherein r denotes interleaving depth.
5. The wireless device of claim 4 , wherein the wireless interface and processing circuitry are further operable to:
group B bits of the second bit sequence to form subsymbols and group subsymbols into blocks comprising
K
rot
subsymbols; and
wherein rot is the number of blocks transmitted via each of the N OFDM transmit streams and is any integer divisor of K.
6. The wireless device of claim 1 , wherein the wireless interface and processing circuitry are further operable to distribute the blocks of subsymbols across the N OFDM transmit streams according to an index, m, defined by the formula:
m =(rot* q *( N− 1)+ p )mod( N *rot);
wherein p=N *(0: rot−1)+ q ; and
wherein rot denotes any integer divisor of K, q denotes integer values such that 0≦q≦N−1, N denotes the number of OFDM transmit streams having indexes 0 through N−1; and (0:rot−1) denotes the sequence 0, 1, 2, . . . , (rot−1).
7. The wireless device of claim 1 , wherein the wireless interface and processing circuitry are further operable to be mode compliant with the Institute of Electrical and Electronics Engineers (IEEE) 802.11a standard (1999) and/or successor standards.
8. The wireless device of claim 1 , wherein the wireless interface and processing circuitry are further operable to be mode compliant with the Institute of Electrical and Electronics Engineers (IEEE) 802.11g standard (2003) and/or successor standards.
9. The wireless device of claim 1 , wherein the wireless interface and processing circuitry are further operable to transmit the N OFDM transmit streams via at least two antennas.
10. The wireless device of claim 9 , wherein transmitting the N OFDM transmit streams via at least two antennas is performed via Multiple Input Multiple Output (MIMO) transmit operations.
11. A wireless device comprising:
a wireless interface; and
processing circuitry, the wireless interface and the processing circuitry operable to process bits of an input symbol for transmission via a plurality of orthogonal frequency division multiplex (OFDM) transmit signals by:
for at least two interleaving operations:
interchanging bits of the input symbol according to respective associated permutations;
allocating bits of the input symbol to form subsymbols, each subsymbol associated with a subcarrier of one of the plurality of OFDM transmit signals;
block mapping groups of subsymbols into blocks of subsymbols; and
rotating the blocks of subsymbols between the plurality of OFDM transmit signals.
12. The wireless device of claim 11 , wherein the wireless interface and processing circuitry are further operable to allocate bits of an input symbol to OFDM transmit streams in a mode selected from a plurality of modes.
13. The wireless device of claim 11 , wherein the wireless interface and processing circuitry are further operable to be mode compliant with the Institute of Electrical and Electronics Engineers (IEEE) 802.11a standard (1999) and/or successor standards.
14. The wireless device of claim 11 , wherein the wireless interface and processing circuitry are further operable to be mode compliant with the Institute of Electrical and Electronics Engineers (IEEE) 802.11g standard (2003) and/or successor standards.
15. The wireless device of claim 11 , wherein the wireless interface and processing circuitry are further operable to transmit the plurality of OFDM transmit signals via at least two antennas.
16. The wireless device of claim 11 , wherein transmitting the plurality of OFDM transmit signals via at least two antennas is performed via Multiple Input Multiple Output (MIMO) transmit operations.
17. A method of operating a wireless device comprising:
processing bits of an input symbol to form N orthogonal frequency division multiplex (OFDM) transmit streams across K subcarriers, wherein at least one input symbol comprises KN subsymbols, wherein at least one of the KN subsymbols comprises B bits of the input symbol and wherein each subsymbol is communicated via an associated subcarrier of the N transmit streams, the processing by:
interleaving the bits of the input symbol by at least one permutation to form permutated bits;
grouping permutated bits into subsymbols;
grouping the subsymbols into blocks of subsymbols; and
rotating the blocks of subsymbols between the N OFDM transmit streams, wherein N is greater than 1.
18. The method of claim 17 , further comprising transmitting the N OFDM transmit streams via at least two antennas.
19. The method of claim 17 , further comprising transmitting the N OFDM transmit streams via at least two antennas is performed via Multiple Input Multiple Output (MIMO) transmit operations.
20. The method of claim 17 , wherein the at least one permutation is compliant with at least one of:
the Institute of Electrical and Electronics Engineers (IEEE) 802.11a standard (1999) and/or successor standards; and
the Institute of Electrical and Electronics Engineers (IEEE) 802.11g standard (2003) and/or successor standards.