초록 ▼

The present invention discloses an OFDM transmission system providing a high level of performance on a variety of frequency selective channels by using a code having the characteristics of maximum PPD and maximum PECL, and a constellation having size 2.sup.n where n generally is greater than k+1, wh

The present invention discloses an OFDM transmission system providing a high level of performance on a variety of frequency selective channels by using a code having the characteristics of maximum PPD and maximum PECL, and a constellation having size 2.sup.n where n generally is greater than k+1, where k is the number of bits in each symbol input to the convolutional encoder. The codes are designed to allow high SNR subchannels to carry their full potential of information which is then used to compensate for information lost on low SNR subchannels.

대표청구항 ▼

[ What is claimed is:] [15.] A method for encoding input symbols to generate interleaved encoded signal points for modulation and transmission through a medium, comprising the steps of:encoding an input symbol to generate an encoded symbol by using a convolution code having maximum periodic effectiv

[ What is claimed is:] [15.] A method for encoding input symbols to generate interleaved encoded signal points for modulation and transmission through a medium, comprising the steps of:encoding an input symbol to generate an encoded symbol by using a convolution code having maximum periodic effective code length and maximum periodic product distance, wherein said convolutional code is determined by:a) choosing k, the number of information bits in said input symbol;b) choosing n, the number of bits in said encoded symbol;c) choosing M, the number of states of said code;d) choosing P, the period of an interleaver;e) determining maximum possible PECL, periodic effective code length, as a function of the number of information bits in said input symbol, the number of bits in said encoded symbol, and the number of states of said code;f) identifying a set of codes having said maximum possible periodic effective code length;g) labeling a constellation with 2.sup.n points to maximize minimum distances associated with error patterns;h) for each code in said identified set of codes, using the labeled constellation to compute periodic product distances of orders Pi) selecting from said set of codes a code having a relatively large value of said linear combination and a relatively large periodic product distances at each order from Pmapping said encoded symbol to a constellation signal point in a defined constellation; andinterleaving a plurality of the constellation signal points to produce interleaved encoded signal points.