Two-Way Relay Channel Estimation Using Segmented Forward and Backward Phases
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Solution Overview
Problem
Two-way relay systems face challenges in accurately estimating channel information and designing relay filters, especially when multiple antennas are involved, which hinders effective self-interference cancellation and spectral efficiency.
Innovation Solution
A two-way relay system with a plurality of antennas that includes a receiver for signal reception, a controller for channel estimation and precoder calculation, and a transmitter for precoded signal transmission, allowing for effective channel estimation and relay filter design even when channel information is not accurately known, minimizing mean square error and enabling self-interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If channel estimation is performed using conventional methods assuming accurate channel information, then self-interference cancellation can be achieved, but the method cannot be extended to multi-antenna systems
Solution Approach 1:
The patent segments the channel estimation process into two distinct phases: first estimating the forward channel from terminals to relay, then estimating the backward channel from relay to terminals. This segmentation allows the system to handle multi-antenna configurations by treating each directional channel separately, overcoming the limitation of conventional single-phase estimation methods.
Solution Approach 2:
The patent performs preliminary channel estimation using reference signals transmitted during specific time slots before actual data transmission. By pre-estimating the channels and calculating relay filters in advance, the system prepares necessary channel information without requiring perfectly accurate real-time channel knowledge, enabling multi-antenna operation.
2Reliability
If relay filter design is performed assuming accurate channel information, then optimal performance can be achieved, but system overhead increases
Solution Approach 1:
The patent applies partial action by estimating only the necessary channel components required for relay filter design rather than attempting to obtain complete and perfectly accurate channel information. The system estimates forward and backward channels using reference signals and calculates relay filters based on these partial estimates, achieving sufficient performance without the overhead of exhaustive channel measurement.
Solution Approach 2:
The patent changes the approach from requiring precise channel parameters to using estimated channel parameters with acceptable accuracy. By modifying the channel estimation precision requirements and using statistical channel knowledge, the system reduces measurement overhead while maintaining reliable self-interference cancellation performance.
3Ease of manufacture
If conventional channel estimation methods are used, then implementation is simple, but they cannot resolve limitations in multi-antenna two-way relay systems
Solution Approach 1:
The patent maintains implementation simplicity by segmenting the channel estimation into straightforward sequential steps: estimate forward channel, estimate backward channel, calculate relay filters. This segmented approach avoids complex simultaneous estimation algorithms while effectively handling multi-antenna systems through systematic processing of each channel direction.
Solution Approach 2:
The patent preserves ease of implementation by performing preliminary channel estimation using standard reference signal procedures before data transmission. This preliminary action uses conventional estimation techniques that are simple to implement, yet enables multi-antenna operation by preparing channel knowledge in advance for filter design.
Data Source
AI summary
One or more embodiments provide an apparatus and a method to estimate channel information even when channel information is not accurately known and design a relay filter based on the estimated information in a two-way relay system where a terminal having a single antenna and a relay exist. A relay apparatus of a two-way relay system includes a receiver, a controller, and a transmitter. The receiver receives a signal from at least one terminal. The controller estimates a channel between the terminals based on the received signal, and calculates a receiver matrix and a precoder. The transmitter transmits a signal precoded by the precoder.