Coordinated Downlink Transmissions for Relay Nodes
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Solution Overview
Problem
In wireless communication systems, particularly in LTE and LTE-Advanced networks, there is a challenge in enhancing signal coverage and throughput while maintaining efficient battery usage for user agents (UAs), as existing technologies do not effectively leverage relay nodes to combine signals coherently and coordinate retransmissions efficiently across access nodes and relay nodes.
Innovation Solution
The implementation of a method where access nodes and relay nodes transmit the same information simultaneously to UAs, using coordinated control information and data transmission parameters, allowing for coherent signal combination and efficient retransmissions, thereby improving signal quality and data throughput. This includes the use of layer two and layer three relay nodes, which can demodulate, re-encode, and retransmit data, and the employment of non-adaptive synchronous HARQ retransmissions to reduce backhaul load and simplify cooperative retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay nodes are used to extend coverage and enhance signal, then signal quality and coverage are improved, but system complexity and coordination overhead increase
Solution Approach 1:
The patent merges the transmission functions of access nodes and relay nodes by coordinating their downlink transmissions to user agents. The access node and relay node transmit the same data simultaneously using coordinated control information, combining their signals to improve signal quality and coverage while managing system complexity through standardized coordination protocols.
Solution Approach 2:
The access node acts as an intermediary that coordinates control information to both the relay node and the user agent. This intermediary role enables synchronized transmissions between the access node and relay node, allowing the relay node to extend coverage effectively while the access node manages the coordination overhead.
2Productivity
If simultaneous transmissions from access node and relay node are coordinated, then data throughput is improved, but control information overhead and processing complexity increase
Solution Approach 1:
The access node determines control information for its own downlink transmission and the relay node's downlink transmission in advance, before the actual transmissions occur. This preliminary determination of control information for both nodes enables coordinated simultaneous transmissions that improve data throughput, while the advance planning reduces real-time processing complexity during the actual transmission phase.
3Area of stationary object
If relay nodes demodulate and re-encode data, then signal coverage is extended, but energy consumption and processing load increase
Solution Approach 1:
The relay node performs partial processing by demodulating and re-encoding only the necessary data for coverage extension, rather than full processing of all data types. This partial action enables the relay node to extend coverage area effectively while managing its energy consumption and processing load by focusing only on the essential signal processing functions needed for coverage enhancement.
Data Source
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AI summary
A method for transmitting data to a user agent. The method includes a relay node receiving information from an access node, the information containing the data that is to be transmitted to the user agent and control information that the access node will use to transmit the data to the user agent. The method further includes the relay node transmitting the data to the user agent at the time the access node transmits the data to the user agent, the relay node using the control information that the access node uses to transmit the data to the user agent.