Method and system for selecting cyclic prefix length based on signal quality reports
First Claim
1. A method of adjusting a length of a cyclic prefix used in orthogonal frequency division multiplexing (OFDM) communications, comprising:
- transmitting, through an access point, OFDM signals using a first cyclic prefix length;
receiving a first plurality of signal quality reports from user devices being served by said access point, wherein each of said signal quality reports indicates a reported signal quality value;
determining a distribution of reported signal quality values based on said first plurality of signal quality reports;
selecting a second cyclic prefix length based, at least in part, on said first plurality of signal quality reports, wherein selecting said second cyclic prefix length based, at least in part, on said signal quality reports comprises selecting said second cyclic prefix length based, at least in part, on said distribution of reported signal quality values; and
transmitting, through said access point, OFDM signals using said second cyclic prefix length.
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Accused Products
Abstract
During a first time interval, an access point transmits orthogonal frequency division multiplexing (OFDM) signals using a first cyclic prefix length. The access point receives a plurality of signal reports, such as Channel Quality Indicators (CQIs), from user devices being served by the access point. Based on the signal reports, the access point determines a distribution of signal qualities experienced by the user devices. The access point selects a second cyclic prefix length based, at least in part, on the distribution of signal qualities. The access point transmits OFDM signals using the second cyclic prefix length during a second time interval.
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Citations
19 Claims
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1. A method of adjusting a length of a cyclic prefix used in orthogonal frequency division multiplexing (OFDM) communications, comprising:
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transmitting, through an access point, OFDM signals using a first cyclic prefix length; receiving a first plurality of signal quality reports from user devices being served by said access point, wherein each of said signal quality reports indicates a reported signal quality value; determining a distribution of reported signal quality values based on said first plurality of signal quality reports; selecting a second cyclic prefix length based, at least in part, on said first plurality of signal quality reports, wherein selecting said second cyclic prefix length based, at least in part, on said signal quality reports comprises selecting said second cyclic prefix length based, at least in part, on said distribution of reported signal quality values; and transmitting, through said access point, OFDM signals using said second cyclic prefix length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of adjusting a length of a cyclic prefix used in orthogonal frequency division multiplexing (OFDM) communications, comprising:
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during a first time interval, an access point transmitting OFDM signals using a first cyclic prefix length; said access point receiving a plurality of signal quality reports from a plurality of user devices being served by said access point, wherein each signal quality report indicates one of M preset signal quality values ranging from Ql to QM; for each signal quality value Qi from Ql to QM, determining a number of times, Ri, that said signal quality value, Qi, was indicated in said plurality of signal quality reports, to provide a distribution of signal quality values; selecting a second cyclic prefix length based, at least in part, on said distribution of signal quality values; and during a second time interval, said access point transmitting OFDM signals using said second cyclic prefix length. - View Dependent Claims (12, 13, 14, 15)
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16. A system, comprising:
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a transmitter for transmitting OFDM signals to user devices, wherein said OFDM signals include a cyclic prefix with a cyclic prefix length; a receiver for receiving signal quality reports from said user devices; and a controller coupled to said transmitter and said receiver, wherein said controller is configured to adjust said cyclic prefix length periodically based, at least in part, on said signal quality reports by a process comprising;
(i) controlling said transmitter to use a first cyclic prefix length during a first time interval;
(ii) determining a distribution of signal qualities experienced by said user devices based on signal quality reports received by said receiver;
(iii) selecting a second cyclic prefix length based, at least in part, on said distribution; and
(iv) controlling said transmitter to use said second cyclic prefix length during a second time interval. - View Dependent Claims (17, 18, 19)
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Specification