Name
Abstract | ||
|---|---|---|
The sphere-packing bound Esp(R) bounds the reliability function for fixed-length block-cod es. For symmetric channels, it remains a valid bound even when strictly causal noiseless feedback is allowed from the decoder to the encoder. To beat the bound, the problem must be changed. While it has long been known that variable-length block codes can do better when trading-off error probability with expected block-length, this correspondence shows that the fixed-delay setting also presents such an opportunity for generic channels. While Esp(R) continues to bound the tradeoff between bit error and fixed en d-to-end latency for symmetric channels used without feedback, a new bound called the "focusing bound" gives the limits on what can be done with feedback. If low-rate reliable flow-control is free (ie. the noisy channel has strictly positive zero-error capacity), then the focusing bound can be asymptotically achieved. Even when the channel has no zero-error capacity, it is possible to substantially beat the sphere-packing bound by synthesizing an appropriately reliable channel to carry the flow-control information. |
Year | Venue | Keywords |
|---|---|---|
2006 | Clinical Orthopaedics and Related Research | information theory,error probability,flow control,reliability function,sphere packing,block codes |
Field | DocType | Volume |
Discrete mathematics,Chapman–Robbins bound,Binary symmetric channel,Mathematical optimization,Combinatorics,Latency (engineering),Block code,Communication channel,Beat (music),Encoder,Hamming bound,Mathematics | Journal | abs/cs/061 |
Citations | PageRank | References |
2 | 0.50 | 5 |
Authors | ||
1 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Anant Sahai | 1 | 35 | 4.97 |