PID (Partial Inversion Data): An M-of-N Level-Encoded Transition Signaling Protocol for Asynchronous Global Communication

Abstract

A new delay-insensitive (DI) data encoding protocol for asynchronous global communication is proposed. It is an M-of-N Non-Return-to-Zero (NRZ) protocol and it is levelencoded, meaning that the decoding process simply uses the values of the codeword not their transitions. It has significant power and throughput benefits with respect to Return-to-Zero (RZ) codes, since no return-to-zero-phase is required. The proposed protocol also has a better (or equal) coding efficiency and it requires a similar decoding hardware as existing 1-of-N level-encoded NRZ codes (i.e., 1-of-2 LEDR and 1-of-N LETS), while it has worse (or equal) coding efficiency but requires significantly smaller decoding hardware than existing M-of-N transition-encoded NRZ codes. In particular, the 2-of-7 code, which encodes 4 data bits, completely dominates all other known DI NRZ codes since it has equal coding and power efficiency but less hardware overhead than transition-encoded ones, and it has equal power efficiency and hardware overhead but better coding efficiency than LETS.