Back to results
US 7,889,806 B2Granted
Method and apparatus to improve performance in a multicarrier MIMO channel using the hadamard transform
AssigneeIntel Corporation
InventorsAndrey V Belogolovy, Vladislav A Chernyshev
Life of this patent
Estimating the term…
Abstract
The Hadamard transform is used to spread data within data blocks in a multicarrier MIMO system, before transmission. In this manner, the negative effects caused by the clustering of bad subcarriers (i.e., subcarriers having a low transmission coefficient due to fading) may be reduced. In at least one embodiment, a MAP-type detection scheme is used in the receiver to extract bit reliabilities from the received signals.
Claims8
A method comprising:
- receiving a vector Y from a multicarrier MIMO channel by a receiver, said vector Y having a plurality of symbols;
- grouping said symbols of said vector Y into multiple blocks of size M using a Hadamard transformer, where M is the size of a Hadamard matrix used to Hadamard transform source blocks in a corresponding transmitter;
- and
- performing the following for a first block in said multiple blocks:
- calculating an estimated received vector for each possible vector of length M of source symbols;
- generating a list with said estimated received vectors;
- and
- using said list to generate bit reliabilities for use in decoding said vector Y
- wherein using said list includes performing the following for a first bit position of a bit sequence:
- first examining said list to find an estimated received vector with a lowest Euclidean distance (d0) to said first block among listed vectors having a zero in said first bit position of a corresponding source bit sequence:
- second examining said list to find an estimated received vector with a lowest Euclidean distance (d1) to said first block among listed vectors having a one in said first bit position of a corresponding source bit sequence;
- and
- calculating a bit reliability for said first bit position using d0 and d1.
10 more elements
An apparatus comprising:
- a combiner to combine signals received by multiple receive antennas from a multicarrier MIMO channel to generate a received vector Y having a plurality of symbols;
- and
- a demapper/demodulator including:
- logic to divide said symbols of said received vector Y into multiple blocks of length M, where M is the size of a Hadamard matrix used in a corresponding transmitter;
- and
- logic to, for a first block in said multiple blocks, calculate an estimated received vector for each possible vector of length M of source symbols, generate a list with said estimated received vectors, and use said list to generate bit reliabilities
- wherein said logic to use said list to generate bit reliabilities includes:
- first logic to examine said list to find an estimated received vector with a lowest Euclidean distance (d0 ) to said first block among listed vectors having a zero in a first bit position of corresponding source bit sequences;
- second logic to examine said list to find an estimated received vector with a lowest Euclidean distance d1 to said first block among listed vectors having a one in said first bit position of corresponding source bit sequences;
- and
- third logic to calculate a bit reliability for said first bit position using d0 and d1.
8 more elements
Dependencies are inferred from the claim text.