Bit level diversity combining for COFDM system
AssigneeKoninklijke Philips Electronics N.V.
InventorsMonisha Ghosh, Joseph Patrick Meehan, Xuemei Ouyang
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Abstract
Bit level, rather than symbol level, diversity combining is employed within a wireless communications receiver. Channel estimates and bit metrics are separately computed for signals received by different antenna elements. Bit metrics are calculated by determining a least squares cumulative difference between all bits within the received symbol and corresponding bits within constellation symbols as modified by the channel estimate. The separately-determined bit metrics are then combined for decoding. Performance improvements over both single antenna systems and multiple antenna systems with symbol level diversity combining are achieved.
Claims20
A wireless receiver comprising:
- for each of a plurality of antenna elements employed to receive a wireless signal, separate channel estimation units and bit metric calculation units, wherein each bit metric calculation unit determines bits for each received symbol from a corresponding antenna element based on a corresponding channel estimate;
- a signal combiner combining outputs of the separate bit metric calculation units;
- and
- a decoder receiving and operating on an output of the signal combiner.
A wireless communications system comprising:
- a transmitter;
- a channel by which a wireless signal from the transmitter is transmitted;
- and
- a receiver receiving the wireless signal from the channel, wherein the receiver comprises:
- for each of a plurality of antenna elements employed to receive a wireless signal, separate channel estimation units and bit metric calculation units, wherein each bit metric calculation unit determines bits for each received symbol from a corresponding antenna element based on a corresponding channel estimate;
- a signal combiner combining outputs of the separate bit metric calculation units;
- and
- a decoder receiving and operating on an output of the signal combiner.
A method of receiving a wireless signal comprising:
- for each of a plurality of antenna elements employed to receive the wireless signal, separately estimating the channel estimation and calculating bit metrics, wherein each bit metric calculation determines bits for each received symbol from a corresponding antenna element based on a corresponding channel estimate;
- combining outputs of the separate bit metric calculations;
- and
- decoding the combined outputs.
A partially processed wireless signal comprising:
- separate bit metrics for each of a plurality of antenna elements employed to receive a wireless signal, wherein each bit metric is derived from bits for each received symbol from a corresponding antenna element based on a corresponding channel estimate for that antenna element.
Dependencies are inferred from the claim text.