Lower bounds on rate of fixed-length source codes under average- and 6-fidelity constraints
Pierre Moulin · 2017
This paper studies lossy coding of discrete memoryless sources and derives new asymptotic lower bounds on the rate of optimal fixed-length codes. Both average and excess-probability distortion constraints are studied. We show that in each case the rate of optimal codes is lower bounded by R(D) + R2/ √ n + (log n)/(2n) + R4/n + o(1) where n is the block length, R(D) is Shannon's rate-distortion function, R2is the second-order coding rate, and R4a constant that is explicitly identified.