LTE-A Uplink Transmit Diversity via Cyclic Shifted Frequency Overlap
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Solution Overview
Problem
Current communication systems, particularly in LTE-A uplink, face challenges in achieving high reception quality due to the inability to use transmit antennas for both frequency allocation and diversity, limiting the potential for improved reception quality.
Innovation Solution
A communication apparatus and method that involves mapping data signal sequences onto the frequency axis, allowing partial overlap and cyclic shifting to enable simultaneous transmission from multiple antennas, along with precoding and equalization using SIMO and MIMO weights to manage interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different frequency allocation is made for each transmit antenna, then spatial multiplexing transmission with high reception quality can be performed, but transmit antennas cannot be used to improve reception quality through transmit diversity
Solution Approach 1:
The patent segments the frequency allocation into two parts: a first frequency allocation for spatial multiplexing transmission and a second frequency allocation for transmit diversity transmission. This segmentation allows each transmit antenna to have dedicated frequency resources for both transmission modes, resolving the contradiction between achieving high reception quality through spatial multiplexing and maintaining transmit diversity capability.
2Reliability
If the same data is transmitted from multiple transmit antennas, then transmit diversity gain can be obtained, but interference occurs when frequency allocations overlap
Solution Approach 1:
The patent introduces a cyclic shift as an intermediary mechanism to resolve interference. By applying different cyclic shifts to the same data transmitted from different antennas, the patent enables the receiver to separate and combine signals constructively, achieving transmit diversity gain while eliminating harmful interference through the mediating effect of cyclic shifting.
3Use of energy by moving object
If single-carrier transmission is used for uplink, then PAPR is low and wide coverage is maintained, but the ability to use multiple antennas for both frequency allocation and diversity is limited
Solution Approach 1:
The patent introduces dynamic frequency allocation for single-carrier transmission, where frequency resources are dynamically assigned to different transmit antennas based on channel conditions. This dynamic approach enables single-carrier transmission to achieve both low PAPR and enhanced multi-antenna capability, as the system can adaptively utilize multiple antennas for both spatial multiplexing and diversity transmission without requiring multi-carrier schemes.
Data Source
AI summary
There are included a plurality of mapping units to which a plurality of data signal sequences related to the same data signal sequence are input via spectra cyclic shift units and which arrange the input data signal sequences on the frequency axis and output the arranged data signal sequences as transmission frequency spectra; an assignment information acquisition unit that controls the plurality of mapping units based on assignment information to cause the data signal sequences arranged on the frequency axis to partially overlap; the spectra cyclic shift units shifting, under control of an amount-of-shift decision unit, the input data signal sequences by an amount of cyclic shift to cause partially overlapping data signals to be identical and outputting the data signal sequences; and a plurality of transmit antennas that send out the transmission frequency spectra output by the plurality of mapping units.