Base Station Remote Unit MLD for Partial Centralization
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Solution Overview
Problem
In wireless communication systems, especially in partial centralization configurations, performing uplink CoMP (Coordinated Multi-Point) transmission is challenging due to the distribution of physical layer functions, which prevents MIMO signal detection and increases transmission capacity requirements between remote units and the central unit.
Innovation Solution
Implementing maximum likelihood decision (MLD) in each remote unit using local reception signals and channel information, with the central unit selecting signals based on propagation loss, allowing uplink CoMP even with distributed physical layer functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If physical layer functions are distributed in partial centralization configuration, then system flexibility and scalability are improved, but MIMO signal detection capability is lost and transmission capacity requirements increase
Solution Approach 1:
The patent segments the base station into a central unit and multiple remote units, distributing physical layer functions across these segments. Each remote unit independently performs MLD and signal detection locally, eliminating the need for high-capacity transmission to a central unit while maintaining system flexibility and scalability.
Solution Approach 2:
Each remote unit performs self-service by independently executing maximum likelihood detection and signal detection using local reception signals and channel information. This self-contained approach eliminates dependency on central unit processing capacity and reduces transmission requirements while maintaining full MIMO functionality.
2Reliability
If maximum likelihood decision is performed in each remote unit, then uplink CoMP capability is maintained with distributed functions, but computation load at remote units increases
Solution Approach 1:
The patent performs channel estimation and preparation of detection parameters in advance at each remote unit using local reception signals. By pre-processing channel information and preparing detection parameters, the actual MLD computation during CoMP operation is reduced, maintaining uplink CoMP capability while managing computation load.
Solution Approach 2:
Each remote unit performs MLD and signal detection using only local reception signals and locally estimated channel information, rather than requiring centralized processing. This local quality approach enables distributed CoMP functionality while allowing each unit to optimize its computation based on local conditions.
3Measurement precision
If signals are received at multiple remote units for CoMP, then signal quality at cell edge is improved, but transmission capacity between remote units and central unit must be extremely large
Solution Approach 1:
The patent extracts the signal detection and MLD functions from the central unit and places them at each remote unit. Each remote unit independently detects signals using local reception signals and channel information, eliminating the need for high-capacity transmission to a central unit while maintaining improved signal quality through multi-point reception.
Solution Approach 2:
The patent segments the signal detection process across multiple remote units, with each unit performing independent MLD and signal detection. This segmentation allows parallel processing at multiple locations, improving signal quality through diversity while avoiding the need for aggregate high-capacity transmission to a single central unit.
Data Source
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AI summary
A base station apparatus is provided with: at least one remote unit apparatus each including at least one antenna; and a central unit apparatus connected to each remote unit apparatus via a transmission path. The antenna provided in the remote unit apparatus receives a transmission signal wirelessly transmitted from at least one wireless terminal each including at least one antenna. The remote unit apparatus is provided with: a channel estimation unit that estimates channel information between the antenna of the wireless terminal and the antenna of the remote unit apparatus, using a reception signal received by the antenna provided in the remote unit apparatus; a reception signal processing unit that detects a reception signal corresponding to the transmission signal by performing maximum likelihood decision on the reception signal, using the channel information estimated by the channel estimation unit; a decoding unit that decodes each signal detected by the reception signal processing unit; and an inter-unit transmission unit that transmits each signal decoded by the decoding unit to the central unit apparatus. The central unit apparatus is provided with: an inter-unit receiving unit that receives each signal transmitted from the inter-unit transmission unit; and a signal selection unit that acquires the channel information from the channel estimation unit, and selects a signal corresponding to each transmission signal transmitted from the wireless terminal, from among signals received by the inter-unit receiving unit, based on the acquired channel information.