Uplink SU-MIMO Layer Mapping for LTE Peak Data Rate
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Solution Overview
Problem
Current LTE technology only supports single antenna transmission on the uplink, limiting peak data rate and spectral efficiency, and faces challenges in implementing Single-User Multiple Input, Multiple Output (SU-MIMO) while maintaining backward compatibility and minimizing control signaling overhead.
Innovation Solution
The method involves receiving and precoding codewords, permuting them, and transmitting them on multiple antennas using the same codeword-to-layer mapping scheme as in downlink SU-MIMO, introducing layer or codeword diversity to equalize Signal to Interference plus Noise Ratio (SINR) across codewords, and optimizing control overhead through ACK/NAK bundling and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single antenna transmission is used on the uplink, then device complexity is low, but peak data rate and spectral efficiency are limited
Solution Approach 1:
The patent segments the uplink transmission by introducing multiple codewords (CW1, CW2) that can be independently mapped to different layers and antennas. Each codeword can be transmitted through different spatial paths, enabling the system to achieve MIMO benefits while maintaining manageable complexity through structured segmentation of the transmission stream.
Solution Approach 2:
The patent transitions from single-antenna uplink transmission to multi-antenna transmission by adding a spatial dimension. Multiple codewords are mapped to different layers which are then transmitted through multiple antennas, effectively adding a spatial dimension to the communication and thereby increasing peak data rate and spectral efficiency.
2Productivity
If SU-MIMO is implemented on the uplink, then spectral efficiency is improved, but control signaling overhead increases
Solution Approach 1:
The patent merges the control signaling for multiple codewords into a unified grant structure. The eNodeB transmits a single downlink grant that contains control information for multiple uplink codewords, combining what would otherwise be separate control signals into one consolidated message, thereby reducing control overhead while maintaining SU-MIMO spectral efficiency.
Solution Approach 2:
The patent creates a universal downlink grant structure that can accommodate multiple codewords and various MIMO configurations. This multi-functional grant structure can serve different transmission scenarios (single codeword, multiple codewords, different layer mappings) through a single standardized format, reducing the need for separate control signaling for each configuration.
3Reliability
If layer permutation is used to equalize SINR, then communication reliability is improved, but processing complexity increases
Solution Approach 1:
The patent applies layer permutation as a preliminary action before the actual data transmission. By permuting the layers of the codewords in advance and mapping them to different antennas according to a predefined pattern, the system equalizes SINR across codewords before transmission occurs. This preliminary structuring simplifies the overall processing by preparing the signal in advance rather than requiring complex real-time adjustment.
Data Source
AI summary
This invention is a method and an apparatus to up link transmission of data from a user equipment to a base station for single user multiple input, multiple output. This invention includes receiving at least one codeword, permuting the received codewords, precoding the permuted codewords and transmitting the predecoded codewords on plural antennas. The codewords may be permuted by layer permutation or by codeword permutation.