Embedded Pilot Signal Channel Estimation Without Signaling Overhead
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in channel estimation due to significant signaling overhead, which reduces bandwidth and system capacity, particularly in MIMO networks, as they require separate pilot signals for each antenna, leading to increased time slots and complex interference cancellation techniques.
Innovation Solution
The method involves combining pilot signals with data symbols and transmitting them simultaneously, with the pilot signal power being below the data symbol power, allowing for channel estimation without additional signaling overhead, using a technique that embeds pilot signals within data symbols and employs circularly shifted pilot sequences in MIMO systems to reduce the need for complex cancellation circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pilot signals are transmitted separately from data symbols, then channel estimation accuracy is improved, but signaling overhead increases and bandwidth for user traffic decreases
Solution Approach 1:
The patent combines pilot signals and data symbols into a single transmission signal. The pilot signal is embedded within the data symbol structure, allowing both channel estimation and user data transmission to occur simultaneously in the same time-frequency resources, thereby eliminating the need for separate pilot transmission time slots
Solution Approach 2:
The transmitted signal structure is designed to serve multiple functions simultaneously: it carries user data information while also containing embedded pilot components for channel estimation. This multi-functional approach allows the same signal to fulfill both data communication and channel characterization roles
2Measurement precision
If separate pilot signals are transmitted from multiple antennas in MIMO systems, then channel estimation for each antenna is improved, but signaling overhead increases and system capacity decreases
Solution Approach 1:
The patent merges pilot signal transmission with data symbol transmission in MIMO systems. Each antenna transmits a combined signal containing both pilot and data components, allowing channel estimation for multiple antennas to occur simultaneously with data transmission, thereby maximizing system capacity while maintaining estimation accuracy
Solution Approach 2:
The patent utilizes the spatial dimension in MIMO systems by embedding antenna-specific pilot signatures within the data stream. Each antenna's pilot signal is distinguished through unique coding or positioning in the time-frequency-space domain, enabling separate channel estimation for each antenna without requiring separate transmission resources
3Reliability
If pilot signals are transmitted with high power, then channel estimation reliability is improved, but interference with data symbols increases and receiver complexity increases
Solution Approach 1:
The patent applies local quality by embedding pilot signals at specific locations within the data symbol structure rather than transmitting them as separate high-power signals. The pilot components are positioned in specific time-frequency regions within the symbol, allowing reliable channel estimation without creating widespread interference
Solution Approach 2:
The patent uses signal processing techniques as intermediaries to separate the embedded pilot signal from the data symbol at the receiver. Correlation-based detection and signal subtraction methods act as mediators to extract channel estimation information while canceling pilot interference from the data stream, reducing receiver complexity compared to handling separate high-power pilot signals
Data Source
AI summary
A base station is disclosed for communicating with a subscriber station in a wireless network without requiring training signaling overhead. The base station is capable of combining a pilot signal with a data symbol and transmitting the combined pilot signal and data symbol to the subscriber station. A power level of the pilot signal is below a power level of the data symbol. The base station may be a single-input, single-output (SISO) antenna system or a multiple-input, multiple-output (MIMO) antenna system.