Multi-Stream TCM Reception for High Spectral Efficiency
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving high aggregate spectral efficiencies while maintaining low single-stream Signal-to-Noise Ratio (SNR) losses, especially when dealing with multiple data streams, and have a significant gap with respect to the AWGN channel capacity.
Innovation Solution
The proposed method involves selecting multiple data streams for transmission using Trellis Coded Modulation (TCM) schemes, with stream-specific interleavers and scrambling sequences, and combining them into a single transmission signal, optimizing the number of streams based on channel quality and using specific modulation schemes and interleaver permutations to maximize spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple data streams are multiplexed onto the same time-frequency-space resources using OMA schemes, then aggregate spectral efficiency is significantly increased, but single-stream SNR loss increases
Solution Approach 1:
The patent segments the transmission process into distinct functional blocks: TCM encoding, stream-specific interleaving, scrambling with user-specific sequences, and superposition. Each segment processes one or more streams independently before combining, allowing the system to manage multiple streams while maintaining individual stream integrity and minimizing interference-induced SNR loss.
Solution Approach 2:
The patent applies stream-specific processing parameters including user-specific scrambling sequences, stream-specific interleaving patterns, and adaptive TCM scheme selection for each stream. This local customization optimizes each stream's resistance to interference and noise, thereby minimizing single-stream SNR loss while maintaining high aggregate spectral efficiency.
2Productivity
If the number of multiplexed streams is increased, then aggregate data rate is improved, but the gap with AWGN channel capacity increases
Solution Approach 1:
The patent employs dynamic adaptation of TCM scheme parameters including modulation order, code rate, and constellation size based on channel conditions and the number of active streams. This dynamic adjustment allows the system to approach AWGN channel capacity under favorable conditions while maintaining robust performance when multiple streams are multiplexed, thereby reducing the performance gap.
Solution Approach 2:
The patent changes key transmission parameters including TCM encoding rates, interleaver depths, and scrambling sequence lengths as a function of the number of multiplexed streams and channel quality metrics. These parameter adjustments optimize the trade-off between aggregate data rate and reliability, enabling the system to operate closer to theoretical capacity limits.
3Loss of energy
If stream-specific interleaving and scrambling is applied to each data stream, then single-stream SNR loss is reduced, but device complexity increases
Solution Approach 1:
The patent applies stream-specific interleaving and scrambling as preliminary processing steps before superposition and transmission. By pre-processing each stream with user-specific sequences and patterns, the system minimizes inter-stream interference and noise impact before the signals combine, thereby reducing SNR loss. The receiver applies corresponding deinterleaving and descrambling operations to recover individual streams.
Solution Approach 2:
The patent uses stream-specific copies of base processing structures including replicated TCM encoders with user-specific parameters, multiple interleavers with different permutation patterns, and user-specific scrambling sequence generators. These copied but customized components enable independent optimization of each stream while maintaining systematic design that controls overall complexity.
Data Source
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AI summary
The present invention relates to a transmission method and corresponding receiving methods. The transmission method comprises: - selecting K number of data streams for transmission, wherein each data stream comprises one or more data messages; and independently for each data stream k = 0,..., K— 1: - encoding and modulating data messages of the kth data stream using a Trellis Coded Modulation, TCM, scheme TCM k , - interleaving the encoded and modulated data messages of the k-th data stream by using a stream specific interleaver ∏k, - scrambling the interleaved data messages of the k-th data stream by using a stream specific scrambling sequence; - combining all scrambled data messages of the K number of data streams into at least one transmission signal s(Į); and - transmitting the at least one transmission signal s(Į) over a radio channel of the wireless communication system. The receiving method comprises: - receiving the at least one transmission signal according to any of the preceding claims; - computing a joint probability for the modulation symbols of all K streams conditional to the received signal rĮ; and for each data stream k = 0,..., K— 1: a) computing soft information related to the modulation symbols for the kth data stream from the joint probability, b) feeding the soft information related to the modulation symbols through a stream specific deinterleaver ∏k -1 to a TCM k decoder for the k-th data stream, c) decoding the deinterleaved soft information so as to obtain soft information related to information symbols of data messages for the k-th data stream and updated soft information related to the modulation symbols for the k-th data stream, d) feeding the updated soft information related to the modulation symbols for the k-th data stream through a stream specific interleaver ∏k, and e) updating the joint probability with the updated soft information related to the modulation symbols for the k-th data stream; repeating steps a) - e) an arbitrary number of iterations for all K streams, and in the final iteration: - using the soft information related to information symbols for the k-th data stream so as to obtain decoded data messages for the k-th data stream, and - outputting the decoded messages for the k-th data stream.. Furthermore, the invention also relates to a transmitter device, a receive device, a computer program, and a computer program product thereof.