System and method for selecting spreading codes based on multipath delay profile estimation for wireless transceivers in a communication network
First Claim
1. A method for selecting a spreading code for use in communication between nodes in a communication network based on transmission channel Multipath Delay Profiles, comprising the steps of:
- controlling a first node to send a first data packet to a second node via a transmission channel using a spreading-gain code;
estimating a Multipath Delay Profile of said transmission channel based on said issued first data packet;
calculating a fitness function including said Multipath Delay Profile for a plurality of spreading codes of said transmission channel;
selecting a spreading code from a plurality of spreading codes available for said transmission channel based on said fitness function calculation; and
controlling said second node to send a second data packet to said first node, said second data packet including information adapted to inform said first node of said selected spreading code, wherein said fitness function corresponds to where Rxx is the autocorrelation function of the spreading code considered, N is the length of the spreading code considered and MDP is the Multipath Delay Profile.
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Abstract
A system and method for providing optimum wireless communication spreading code selection such that communication channel interpath interference is minimized. In Direct-Sequence Spread-Spectrum, the autocorrelation properties of a spreading code greatly affects the inherent ability of a system to resist multipath. Low/spreading gain codes (or “short” codes) associated with high data rates do not perform well where large-amplitude multipath is present. The system and method presented herein overcomes this problem by selecting spreading codes in such a way that interference caused by multipath is minimized. The system and method does so by determining the characteristics of the radio-frequency link in order to select a spreading code that will minimize interpath interference.
111 Citations
19 Claims
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1. A method for selecting a spreading code for use in communication between nodes in a communication network based on transmission channel Multipath Delay Profiles, comprising the steps of:
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controlling a first node to send a first data packet to a second node via a transmission channel using a spreading-gain code; estimating a Multipath Delay Profile of said transmission channel based on said issued first data packet; calculating a fitness function including said Multipath Delay Profile for a plurality of spreading codes of said transmission channel; selecting a spreading code from a plurality of spreading codes available for said transmission channel based on said fitness function calculation; and controlling said second node to send a second data packet to said first node, said second data packet including information adapted to inform said first node of said selected spreading code, wherein said fitness function corresponds to where Rxx is the autocorrelation function of the spreading code considered, N is the length of the spreading code considered and MDP is the Multipath Delay Profile. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for selecting a spreading code for communication between nodes in a communication network based on transmission channel Multipath Delay Profiles, comprising:
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a first node, adapted to send a first data packet on a transmission channel using a spreading-gain code; and a second node, adapted to receive said first data packet on said transmission channel, and in response, estimate a Multipath Delay Profile of said transmission channel, calculate a fitness function for a plurality of spreading codes of said transmission channel based on said Multipath Delay Profile, select a spreading code from said plurality of spreading codes of said transmission channel based on said fitness function, and send a second data packet to said first node, said second data packet including information adapted to inform said first node of said selected spreading code, and wherein said fitness function corresponds to where Rxx is the autocorrelation function of the spreading code considered, N is the length of the spreading code considered and MDP is said Multipath Delay Profile. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A wireless communications device, adapted to determine and implement spreading code values, comprising:
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a transceiver, said transceiver adapted to send and receive data packets on a transmission channel; and a controller, adapted to estimate a Multipath Delay Profile of said transmission channel based on a received data packet, calculate a fitness function for a plurality of spreading codes of said transmission channel based on said Multipath Delay Profile, and select a spreading code from said plurality of spreading codes of said transmission channel based on said fitness function, and wherein said fitness function corresponds to where Rxx is the autocorrelation function of the spreading code considered, N is the length of the spreading code considered and MDP is said Multipath Delay Profile. - View Dependent Claims (17, 18, 19)
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Specification