Massive MIMO Antenna Grouping via Virtual Channel Selection
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Solution Overview
Problem
Massive MIMO systems face challenges in efficiently combining antenna signals due to pilot contamination, which limits link performance and increases costs per bit, especially in wireless communication systems like LTE, where the number of antennas exceeds a threshold, leading to interference and reduced channel estimation accuracy.
Innovation Solution
A method for antenna combining in massive MIMO systems involves receiving pilot signals from multiple antennas, selecting reference codebooks based on channel quality, determining virtual channels with minimized distance, and transmitting combining information to group antennas, allowing for efficient signal transmission and reception by allocating orthogonal sequences to these groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antennas is increased to meet massive MIMO requirements, then system capacity and spectral efficiency are improved, but pilot contamination increases and channel estimation accuracy deteriorates
Solution Approach 1:
The patent segments the antenna system by grouping antennas into multiple antenna groups and assigning orthogonal sequences to each group. This segmentation allows the base station to manage pilot signals more effectively by processing them group-by-group, reducing the impact of pilot contamination while maintaining the benefits of a large number of antennas for high system capacity.
2Measurement precision
If antenna combining is performed to reduce pilot contamination, then channel estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameter of signal orthogonality by introducing orthogonal sequences associated with each antenna group. This parameter change allows the system to distinguish between different antenna groups' pilot signals, improving channel estimation accuracy through a systematic approach that manages complexity through structured signal design rather than complex processing algorithms.
3Reliability
If orthogonal sequences are allocated to antenna groups, then pilot contamination is reduced, but frequency resources are consumed
Solution Approach 1:
The patent makes the orthogonal sequences serve multiple functions: they act as pilot signals for channel estimation, enable the base station to identify and separate antenna group signals, and provide the basis for subsequent antenna combining operations. This multi-functionality reduces the need for additional dedicated resources while maintaining pilot orthogonality across antenna groups.
Data Source
AI summary
The base station, receiving first pilot signals transmitted via each of multiple antennas of a user equipment (UE), selects one or more reference codebooks based on channel qualities of the received first pilot signals, and selects one or more sub-channels for each of the reference codebooks. Based on this, the base station determines one or more virtual channels, wherein each of the virtual channels comprises one reference codebook and the one or more sub channels selected for the one reference codebook, wherein the sub-channels are selected to minimum distance between corresponding virtual channel and corresponding reference codebook. And, the base station transmits antenna combining information to the UE, wherein the antenna combining information combines the multiple antennas of the UE into one or more antenna groups corresponding to the one or more virtual channels; and receive second pilot signals transmitted by the UE based on the antenna combining information.