Transmitter method and transmission system using adaptive coding based on channel characteristics

Abstract

A transmitter receives information for transmission to a receiver over a communication channel. A cyclical redundancy checking (CRC) code circuit encodes the information with CRC code for error detection purposes. The CRC coded information is provided to a code switch. The code switch provides the CRC coded information to either a first code circuit or a second code circuit for forward error correction (FEC) coding. The first code circuit may, for example, encode the information using a FEC Code 1, such as convolutional coding, and the second code circuit may encode the information using a FEC Code 2, such as repetition coding. The code switch selects either the first or second code circuit based on detected characteristics of the channel. The channel characteristics may be obtained from a channel estimation circuit, may be obtained from an error feedback signal I.sub.3 from the receiver or may be obtained from a combination of both. After the code switch selects the first or second code circuit, the information is appropriately coded to produce a coded signal which is transmitted over the channel by a transmission circuit.

Dependencies are inferred from the claim text.