High-data-rate frequency-hopping wireless communication system
AssigneeProxim, Inc.
InventorsTony Kirke, Juan Grau, Carlos Puig, Gitty Nasserbakht
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Abstract
A wireless communication system including a receiver adapted to receive data at 10Mbps or greater is described. The received signals are preferably binary (BFSK) and/or quaternary (QFSK) shift keying signals limited to a bandwidth of less than or equal to 5 MHz. The receiver includes a demodulator capable of operating in a multipath environment. In one embodiment, a frequency-hopping wireless communication system is used and the bandwidth limitations concern the bandwidth at each hop.
Claims39
A frequency-hopping wireless communication system including a receiver adapted to receive data at a relatively high data rate, the received signals being binary (BFSK) and/or quaternary (QFSK) frequency shift keying signals limited to a relatively low bandwidth at each frequency hop, the ratio of the data rate to the receiver bandwidth at each frequency hop being greater than one Mbps/MHz in the case of binary frequency shift keying and greater than two Mbps/MHz in the case of quaternary frequency shift keying, the receiver including a demodulator able to operate in a multipath environment.
A frequency shift keying receiver comprising:
- analog elements including a down-converter unit and limiter;
- and
- digital elements including a slope compensation filter, a digital gain control unit, a frequency discriminator unit and a frequency shift keying demodulator.
A frequency shift keying receiver comprising:
- analog elements including a down-converter unit and a limiter;
- a slope compensation filter, the slope compensation filter compensating for frequency distortion induced by the analog elements;
- and
- a frequency discriminator unit after the slope compensation filter.
A receiver adapted to receive data at first and second data rates, the first data rate being associated with quaternary frequency shift keying signals, the second data rate being associated with binary frequency shift keying signals ,the binary and quaternary frequency shift keying signals having the same symbol rate, the receiver including a maximum likelihood sequence detector unit implementing trellis state diagram transition calculations in logic blocks wherein at least some of the logic blocks used to implement the binary frequency shift keying operation are also used in the quaternary frequency shift keying operation.
A receiver comprising:
- an A/D converter adapted to sample at a rate such that there are multiple samples for each transmitted symbol;
- a history convolver unit associated with a maximum likelihood sequence detector, the history convolver unit adapted to produce an estimate of an ideal sample value;
- and
- a sample selection unit including a timing correction unit creating early, on-time, and late error signals using early, on-time, and late samples along with the estimate of an ideal sample value and using the early on-time and late error signals to determine whether to advance, retreat, or not modify the sample slot used in the demodulation.
Dependencies are inferred from the claim text.