Coordinated Multi-Point Transmission Phase Compensation
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Solution Overview
Problem
Coordinated multipoint transmission systems face challenges due to differing propagation delays between transmission points, which cause phase modulation and increase frequency selectivity, leading to interference and reduced spectral efficiency.
Innovation Solution
A processing system determines phase variations based on propagation delay differences between transmission points and transmits this information to manage and compensate for phase variations, allowing for coherent combining of signals at user equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coordinated multipoint transmission is implemented, then spectral efficiency is improved, but propagation delay differences cause phase modulation and increase frequency selectivity, leading to interference
Solution Approach 1:
The patent changes the parameter of transmission timing by introducing a time advance offset that compensates for propagation delay differences between transmission points. This parameter adjustment allows signals from multiple transmission points to arrive at the user equipment with aligned phases, reducing frequency selectivity and interference while maintaining the spectral efficiency benefits of coordinated multipoint transmission
Solution Approach 2:
The patent applies preliminary action by pre-compensating for propagation delay differences before transmission. The network calculates the time advance offset based on measured propagation delays and configures transmission points to transmit signals earlier by this offset amount, ensuring that all signals arrive simultaneously at the user equipment without requiring real-time phase adjustment
2Area of stationary object
If transmission points are separated in space to provide coverage, then service area is expanded, but propagation delay differences increase causing phase modulation
Solution Approach 1:
The patent compensates for the phase coherence degradation caused by spatial separation by introducing a time advance offset parameter. This parameter is calculated based on the propagation delay difference between transmission points and is applied to adjust the transmission timing, thereby restoring phase coherence at the user equipment despite the physical separation of transmission points
Solution Approach 2:
The patent implements feedback by having the user equipment measure the propagation delay from multiple transmission points and report this information to the network. The network then uses this feedback to calculate appropriate time advance offsets and configure the transmission points accordingly, creating a closed-loop system that maintains phase coherence across expanded service areas
Data Source
AI summary
Systems and techniques for communication using coordinated multi-point transmission. In one embodiment, an apparatus comprises at least one processor and a memory storing a set of computer instructions, configured. The processor is configured to cause the apparatus to determine a linear phase variation between at least first and second transmissions from first and second transmission points based at least in part on a propagation delay difference between the first and second transmissions, and transmit the phase variation information for at least the first and the second transmissions. An apparatus configured to operate as a transmission point in a network receives linear phase variation information indicating phase variation experienced by at least one user equipment resulting from a propagation delay difference between at least the apparatus and a second apparatus operating as a second transmission point and manages transmission so as to control phase variation resulting from the propagation delay difference.