SYSTEM AND METHOD FOR MEASURING CHANNEL QUALITY INFORMATION IN A COMMUNICATION SYSTEM

• Main Authors: NANDA, SANJIV, BALACHANDRAN, KRISHNA, EJZAK, RICHARD PAUL, KADABA, SRINIVAS R
• Format: Patent
• Language: English; French
• Published: 09.12.2003
• Edition: 6
• Subjects: BASIC ELECTRONIC CIRCUITRY; CODE CONVERSION IN GENERAL; CODING; DECODING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION; WIRELESS COMMUNICATIONS NETWORKS

A system and method to measure channel quality in terms of signal to interference plus noise ratio for the transmission of coded signals over fading channels in a communication system. A Viterbi decoder metric for the Maximum Likelihood path is used as a channel quality measure for coherent and non-coherent transmission schemes. This Euclidean distance metric is filtered in order to smooth out short term variations. The filtered or averaged metric is a reliable channel quality measure which remains consistent across different coded modulation schemes speeds. The filtered metric is mapped to the signal to interference plus noise ratio per symbol using a threshold based scheme. Use of this implicit signal to interference plus noise ratio estimat e is used for the mobile assisted handoff in a cellular system, power control and data rat e adaptation in the transmitter.