Cooperative Beamforming Relay Links for Half-Duplex Throughput
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Solution Overview
Problem
Existing cooperative communication methods in wireless systems, such as IEEE 802.11 ad using 60 GHz, face limitations in diversity gain and throughput, particularly in scenarios where relay nodes operate in half-duplex mode and cannot simultaneously transmit and receive signals.
Innovation Solution
Implementing beamforming techniques at the source, relay, and destination nodes, combined with coding schemes like Distributed Space Time Coding (D-STC), Layered Modulation and Coding (LMC), and Network Coding (NC), to enhance data transmission and reception efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If relay nodes operate in half-duplex mode to perform signal transmission and reception, then device complexity is reduced, but productivity (throughput) deteriorates due to inability to simultaneously transmit and receive signals
Solution Approach 1:
The patent applies dynamics by enabling relay nodes to dynamically switch between half-duplex and full-duplex operation modes. The system adapts the relay node's operational state based on channel conditions and traffic requirements, allowing transition from simple half-duplex operation to advanced full-duplex mode with self-interference cancellation capabilities, thereby improving throughput while managing complexity dynamically
2Area of stationary object
If cooperative communication methods are implemented to expand service area, then coverage is improved, but loss of time increases due to additional relay transmission steps
Solution Approach 1:
The patent applies preliminary action through beamforming training and channel estimation performed before actual data transmission. Relay nodes and destination nodes pre-establish beamforming weights and channel state information, so that when data transmission occurs, the signals are already optimized for the cooperative path, reducing the time penalty associated with additional relay transmission steps
Solution Approach 2:
The patent maintains continuity of useful action by enabling simultaneous transmission and reception at full-duplex relay nodes. Multiple cooperative communication paths operate concurrently without interruption, allowing the system to maintain continuous data flow through parallel relay operations rather than sequential half-duplex transmissions
3Productivity
If beamforming is performed to relay node and destination node, then productivity (throughput) is improved, but device complexity increases due to multiple beamforming operations
Solution Approach 1:
The patent merges beamforming operations by combining the beamforming weights for relay node and destination node into a unified precoding structure. Instead of independently computing separate beamforming vectors, the system jointly optimizes the precoding matrix to serve both targets simultaneously, reducing computational complexity while maintaining the throughput benefits of dual beamforming
Data Source
AI summary
A data transmission method of a source node in a cooperative communication system includes: performing a beamforming to a relay node; transmitting data to the relay node; performing a beamforming to a destination node; and transmitting data to the destination node.