Efficient channel shortening for higher order modulation: Algorithm and architecture

Trellis-based channel equalization for GSM/EDGE with 8PSK modulation requires pre-filtering to achieve high performance at acceptable complexity. Since corresponding implementation complexity grows with modulation order, the introduction of 16/32QAM in the latest 2G standard Evolved EDGE requires new solutions to preserve the low-cost attribute of EDGE-enabled devices. This paper describes a novel efficient pre-filter algorithm based on homomorphic filtering. The corresponding hardware implementation in 130 nm CMOS achieves a 5× improvement of area-timing (AT-)product when compared to prior art.