Other

Trellis Phase Communications, LP

John P Fonseka

Eric Morgan Dowling

Muhammad Ahsan Naim

Jin Liu

The present invention provides methods, apparatus and systems for improving a systems-level data rate on a communications link such as the orthogonal frequency division multiplexed multiple access (OFDMA) downlink used in WiFi and LTE cellular/wireless mobile data applications. The present invention preferably uses a form of multilevel coding and decoding known as tiled-building-block encoding/decoding. With the present invention, different receivers coupled to different parallel downlink channels with different channel qualities decode different received signal constellations at different levels of resolution. This allows the downlink of the OFDMA system to operate with a significantly higher data rate, thus eliminating existing inefficiencies in the downlink and significantly increasing system level bandwidth efficiency.

Selective mapping of coded multi-channel transmission

The present invention provides a methods, apparatus and systems for improving a systems-level data rate on a communications link such the orthogonal frequency division multiplexed multiple access (OFDMA) downlink used in used in WiFi and LTE cellular/wireless mobile data applications. The present invention preferably uses a form of multilevel coding and decoding known as tiled-building-block encoding/decoding. With the present invention, different receivers coupled to different parallel downlink channels with different channel qualities decode different received signal constellations at different levels of resolution. This allows the downlink of the OFDMA system to operate with a significantly higher data rate, thus eliminating existing inefficiencies in the downlink and significantly increasing system level bandwidth efficiency.

The present invention provides a methods, apparatus and systems for improving a systems-level data rate on a communications link such theorthogonal frequency division multiplexed multiple access (OFDMA) downlink used in used in WiFi and LTE cellular/wireless mobile data applications. The present invention preferably uses a form of multilevel coding and decoding known as tiled-building-block encoding/decoding. With the present invention, different receivers coupled to different parallel downlink channels with different channel qualities decode different received signal constellations at different levels of resolution. This allows the downlink of the OFDMA system to operate with a significantly higher data rate, thus eliminating existing inefficiencies in the downlink and significantly increasing system level bandwidth efficiency.

The present invention provides a design framework that is used to develop new types of constrained turbo block convolutional (CTBC) codes that have higher performance than was previously attainable. The design framework is applied to design both random and deterministic constrained interleavers. Vectorizable deterministic constrained interleavers are developed and used to design parallel architectures for real time SISO decoding of CTBC codes. A new signal mapping technique called constrained interleaved coded modulation (CICM) is also developed. CICM is then used to develop rate matching, spatial modulation, and MIMO modulation subsystems to be used with CTBC codes and other types of codes. By way of example, embodiments are primarily provided for improved 5G LTE and optical transport network (OTN) communication systems.

Constrained interleaving for 5G wireless and optical transport networks

Serially-concatenated codes are formed in accordance with the present invention using a constrained interleaver. The constrained interleaver cause the minimum distance of the serial concatenated code to increase above the minimum distance of the inner code alone by adding a constraint that forces some or all of the distance of the outer code onto the serially-concatenated code. This allows the serially-concatenated code to be jointly optimized in terms of both minimum distance and error coefficient to provide significant performance advantages. These performance advantages allow a noise margin target to be achieved using simpler component codes and a much shorter interleaver than was needed when using prior art codes such as Turbo codes. Decoders are also provided. Both encoding and decoding complexity can be lowered, and interleavers can be made much shorter, thereby shortening the block lengths needed in receiver elements such as equalizers and other decision-directed loops. Also, other advantages are provided such as the elimination of a error floor present in prior art serially-concatenated codes. That allows the present invention to achieve much higher performance at lower error rates such as are needed in optical communication systems.

Encoding and decoding using constrained interleaving

Serially-concatenated codes are formed in accordance with the present invention using a constrained interleaver. The constrained interleaver cause the minimum distance of the serial concatenated code to increase above the minimum distance of the inner code alone by adding a constraint that forces some or all of the distance of the outer code onto the serially-concatenated code. This allows the serially-concatenated code to be jointly optimized in terms of both minimum distance and error coefficient to provide significant performance advantages. Constrained interleaving can be summarized in that it: 1) uses an outer code that is a block code or a non-recursive convolutional code, and as such, there are multiple codewords present in the constrained interleaver, 2) selects a desired MHD, 3) selects an interleaver size and a set of predefined interleaver constraints to prevent undesired (low-distance) error events so as to achieve the desired MHD, and 4) performs uniform interleaving among the allowable (non-constrained) positions, to thereby maximize or otherwise improve the interleaver gain subject to the constraints imposed to maintain the desired MHD.

Methods, apparatus, and systems for coding with constrained interleaving

Two decoding algorithms are introduced for the decoding of multi-level coded modulation and other types of coded modulation involving component codes and interleaving operations. An improved hard iterative decoding (IHID) algorithm is presented that improves upon a hard iteration decoding technique by adding a stopping criterion. Also, a list Viterbi hard iteration decoding (LV-IHID) algorithm is presented that employs list decoding in conjunction with the IHID algorithm. Both of these decoding algorithms improve upon conventional multi-stage decoding by reducing the effective error multiplicity that is observed at the lowest coding level. It is demonstrated that the LV-IHID algorithm performs close to soft iterative decoding. The computational and delay complexity of the proposed decoding algorithms compare favorably with soft iterative decoding strategies. Also, a novel labeling strategy for MLC design is presented.

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Plano, TX, United States of America

John P Fonseka