Adaptive channel quality estimation algorithm to support link adaptation
First Claim
1. A method to determine a channel quality, as represented by a current bit error probability (BEP) for radio frequency (RF) bursts transmitted from a servicing base station to a wireless terminal in a cellular wireless communication system, the method comprising:
- receiving the RF bursts by the wireless terminal wherein the RF bursts are transmitted according to a transmission scheme;
forming a data block from the RF bursts;
decoding the data block;
determining whether decoding of the data block was successful;
determining a measured quality report for the data block;
when decoding is unsuccessful;
setting the current BEP to a weighted sum of the estimated quality report and a quality report threshold; and
incrementing the quality report threshold by an increment step size until an upper quality report threshold limit is reached;
when decoding is successful;
setting the current BEP to the measured quality report; and
decrementing the quality report threshold by a decrement step size until a lower quality report threshold limit is reached.
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Accused Products
Abstract
RF communications received by a wireless terminal from a servicing base station are used to determine the channel quality such as reported bit error probability (BEP). The RF communications may be in the form of RF bursts that are part of a data frame. An estimated BEP may be determined from the signal to noise ratio (SNR) of the RF bursts and or a sequence of soft decisions extracted from the RF bursts, and their historical performance. The SNR maps to an estimated BEP based upon the modulation format of the RF bursts. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). The reported BEP may be based upon the estimated BEP, RBER, and/or RBER threshold. The RBER threshold may be adaptively incremented or decremented depending upon whether or not the RF communications were properly decoded. The size of the increment or decrement may be based on the channel quality.
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Citations
36 Claims
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1. A method to determine a channel quality, as represented by a current bit error probability (BEP) for radio frequency (RF) bursts transmitted from a servicing base station to a wireless terminal in a cellular wireless communication system, the method comprising:
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receiving the RF bursts by the wireless terminal wherein the RF bursts are transmitted according to a transmission scheme; forming a data block from the RF bursts; decoding the data block; determining whether decoding of the data block was successful; determining a measured quality report for the data block; when decoding is unsuccessful; setting the current BEP to a weighted sum of the estimated quality report and a quality report threshold; and incrementing the quality report threshold by an increment step size until an upper quality report threshold limit is reached; when decoding is successful; setting the current BEP to the measured quality report; and decrementing the quality report threshold by a decrement step size until a lower quality report threshold limit is reached. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A wireless terminal that comprises:
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a Radio Frequency (RF) front end; a baseband processor communicatively coupled to the RF front end; an enCOder/DECoder (CODEC) processing module communicatively coupled to the baseband processor; wherein, the RF front end, the baseband processor, and the CODEC processing module are operable to; receive RF bursts transmitted according to a transmission scheme; form a data block from the RF bursts; decode the data block; determine whether decoding of the data block was successful; determine a current quality report for the data block; when decoding is unsuccessful; set the current quality report to a weighted sum of the estimated quality report and a quality report threshold; and increment the quality report threshold by an increment step size until an upper quality report threshold limit is reached; when decoding is successful; set the current quality report to the measured quality report; and decrement the quality report threshold by a decrement step size until a lower quality report threshold limit is reached. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method to determine a reported bit error probability (BEP) for radio frequency (RF) bursts transmitted from a servicing base station to a wireless terminal in a cellular wireless communication system, the method comprising:
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receiving the RF bursts by the wireless terminal wherein the RF bursts are transmitted according to a transmission scheme; forming a data block from the RF bursts; decoding the data block; determining whether decoding of the data block was successful; determining a current BEP for the data block; when decoding is unsuccessful, setting the reported BEP to a maximum of the estimated BEP and a Re-encoded Bit Error Rate (RBER) threshold, and further incrementing the RBER threshold by a increment step size until an upper quality report threshold limit is reached; and when decoding is successful, setting the reported BEP to the RBER and decrementing the RBER threshold by a decrement step size until a lower quality report threshold limit is reached. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification