Shifting Parameter for Non-Contiguous Sub-Carrier Mapping
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Solution Overview
Problem
Existing MIMO communication systems with OFDM or OFDMA-like schemes face challenges in adapting Alamouti codes when sub-carriers are not consecutive, leading to performance issues due to non-contiguous sub-carrier allocation.
Innovation Solution
A method and device for determining a shifting parameter p to map symbols on sub-carriers, grouping them into clusters with at least one unallocated sub-carrier between clusters, using the formula X′ksecondAnt=ε(−1)k+1X*(p-1-k)mod K, where ε is 1 or −1, to ensure even p and optimal sub-carrier pairing, minimizing performance loss and maintaining signal consistency across antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Alamouti codes are applied to non-contiguous sub-carrier allocation, then frequency diversity is improved, but signal consistency and PAPR control deteriorate
Solution Approach 1:
The patent introduces a shifting parameter p that modifies the mapping relationship between sub-carriers and symbols. By adjusting this parameter, the system adapts the Alamouti code application to non-contiguous sub-carrier allocations while maintaining signal consistency and controlling PAPR. The parameter change transforms the fixed mapping into a flexible one that accounts for cluster-based allocations.
2Adaptability or versatility
If sub-carriers are grouped into clusters with gaps, then frequency selectivity is improved, but Alamouti code performance deteriorates
Solution Approach 1:
The patent applies different mapping strategies to different local regions (clusters) of sub-carriers. Each cluster is treated as a local unit with its own mapping characteristics, allowing the system to optimize for frequency selectivity within clusters while maintaining overall Alamouti code performance through the shifting parameter adjustment.
3Ease of operation
If conventional Alamouti mapping is used with non-contiguous sub-carriers, then implementation simplicity is maintained, but performance loss increases
Solution Approach 1:
The patent maintains implementation simplicity by introducing only a single parameter change (the shifting parameter p) to the conventional Alamouti mapping. This minimal modification preserves the ease of implementation while significantly improving performance in non-contiguous sub-carrier scenarios compared to the conventional fixed mapping approach.
Data Source
AI summary
A method for determining a shifting parameter P to be used by a telecommunication device for mapping symbols on sub-carriers, the telecommunication device including at least two transmit antennas, the symbols being transferred through each antenna of the telecommunication device on at least an even number K, strictly greater than two, of sub-carriers allocated to the telecommunication device. The telecommunication device transfers on a first antenna on each sub-carrier ‘k’, a signal representing a symbol ‘Xk’ in the frequency domain. The telecommunication device transfers on a second antenna on each sub-carrier ‘k’, a signal representing a symbol ‘X′k’ derived from the signal transferred on the first transmit antenna, for each frequency k, by the formula X′KsecondAnt=ε(−1)k+1X*(p-1-k)mod K. Sub-carriers grouped in at least two clusters are allocated to the telecommunication device, and the shifting parameter p is even and determined according to clusters of sub-carriers allocated to the telecommunication device.