MIMO Resource Allocation via Rank-Dependent Offset
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Solution Overview
Problem
Conventional resource allocation solutions for wireless communication systems, particularly in MIMO transmission techniques, fail to optimize the allocation of transmission resources between control information and user data, leading to sub-optimal performance, especially in multi-layer transmissions with low ranks and when sub-optimal precoders are selected.
Innovation Solution
A method for estimating and allocating transmission resources by determining the number of data and control vector symbols based on the transmission rank, using an offset value to adjust the nominal allocation, ensuring efficient use of resources and robustness, particularly for low-rank transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional resource allocation solutions are used for single layer transmission, then resource allocation is simple, but resource allocation becomes sub-optimal for multi-layer MIMO transmissions
Solution Approach 1:
The patent implements dynamic resource allocation by adjusting the number of control vector symbols based on transmission rank. The formula Qc' = Qc × βoffset(r) dynamically scales control resources according to the actual transmission conditions (rank), allowing the system to adapt resource allocation to multi-layer MIMO transmissions while maintaining simplicity for single-layer cases.
Solution Approach 2:
The patent changes the parameter of control vector symbol allocation by introducing a rank-dependent offset factor βoffset(r). This parameter adjustment allows the same basic allocation mechanism to serve both single-layer and multi-layer transmissions optimally, transforming a static allocation scheme into one that responds to transmission conditions.
2Device complexity
If sub-optimal precoder selection is used, then device complexity is reduced, but control signaling performance deteriorates
Solution Approach 1:
The patent applies beforehand cushioning by allocating additional control vector symbols when low transmission ranks are detected. This creates a buffer or cushion that compensates for the performance degradation caused by sub-optimal precoder selection, ensuring control signaling maintains adequate reliability even when using simpler precoding approaches.
Solution Approach 2:
The patent implements preliminary anti-action by proactively increasing control resource allocation in anticipation of potential performance deterioration from sub-optimal precoders. By detecting low transmission ranks and pre-compensating with additional control symbols, the system counteracts the negative effects before they significantly impact control signaling performance.
3Ease of operation
If fixed control vector symbol allocation is used, then allocation simplicity is maintained, but overhead increases for low-rank transmissions
Solution Approach 1:
The patent transforms fixed allocation into dynamic allocation by introducing the offset factor βoffset(r) that adjusts control vector symbol count based on transmission rank. This maintains ease of operation through a simple multiplicative adjustment while reducing overhead for low-rank transmissions by allocating only the necessary control resources.
Data Source
AI summary
A method for wirelessly transmitting data using a plurality of transmission layers includes estimating a number of data vector symbols to be allocated to one or more user data codewords during the subframe and determining a number of bits in the one or more user data codewords. The method also includes calculating a nominal number of control vector symbols to allocate to control information based, at least in part, on the estimated number of data vector symbols and the determined number of bits in the one or more user data codewords. Additionally, the method includes determining an offset value based, at least in part, on a number of layers over which the wireless terminal will be transmitting during the subframe and calculating a final number of control vector symbols by multiplying the nominal number of control vector symbols and the offset value. The method also includes mapping one or more control codewords to the final number of control vector symbols and transmitting vector symbols carrying the one or more user data codewords and the one or more control codewords over the plurality of transmission layers during the subframe.