Joint symbol, amplitude, and rate estimator
View Patent ↗The system in one embodiment relates to tightly integrating parameter estimation, symbol hypothesis testing, decoding, and rate identification. The present invention provides Turbo-decoding for joint signal demodulation based on an iterative decoding solution that exploits error correction codes. The system iteratively couples an initial amplitude estimator, a symbol estimator, a bank of decoders, and a joint amplitude estimator to produce the symbol estimates.
1. A turbo-decoding system for joint signal demodulation, comprising:
a data stream from a plurality of users divided into a plurality of observation intervals;
a plurality of symbol processing nodes processing said observation intervals to compute symbol estimates for said data stream within said observation interval;
a plurality of decoder nodes processing said symbol estimates and producing a plurality of symbol likelihoods;
a plurality of amplitude update nodes processing said symbol likelihoods and calculating a plurality of amplitude update vectors; and
an amplitude estimator node processing said amplitude update vectors and producing an amplitude estimate update, wherein said amplitude estimate update is passed back to said processing nodes for iterative processing between said symbol processing nodes, said decoder nodes, said amplitude update nodes, and said amplitude estimator node until a final condition is obtained.
2. The system according to claim 1 , further comprising a plurality of memory units, wherein at least one memory unit is coupled to each of said processing nodes and to each of said amplitude update nodes.
3. The system according to claim 1 , further comprising a first system area network (SAN) coupling said processing nodes and said decoder nodes, a second system area network (SAN) coupling said decoder nodes and said amplitude update nodes, a third system area network (SAN) coupling said amplitude update nodes and said amplitude estimator, and a fourth system area network (SAN) coupling said amplitude estimator and said processing nodes.
4. The system according to claim 1 , wherein said final condition is selected from at least one of the group consisting of: bit error rate metric level and fixed number of iterations.
5. The system according to claim 1 , wherein said processing nodes, said decoder nodes and said amplitude estimator node are one set of nodes.
6. The system according to claim 5 , wherein said one set of nodes are each comprised of at least one processor.
7. The system according to claim 1 , wherein said likelihood symbols from said decoder nodes are accessible at any time for post-processing.
8. The system according to claim 1 wherein said processing nodes further comprises a thresholder to convert said symbol estimates to symbol bits.
9. The system according to claim 1 , wherein said decoder nodes performs de-interleaving, rate identification, de-puncturing and de-scrambling.