Radio Receiver Channel Estimation Using Reduced DFT Matrix
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing channel estimation units in radio networks have high calculation complexity and require a large number of precalculated values, making them inefficient for determining channel estimates and timing misalignment.
Innovation Solution
A receiver with a channel estimation unit that uses a DFT matrix with a fundamental period related to the number of sub-carriers associated with a user, allowing for a channel estimate of L taps, where L is less than the number of sub-carriers, and incorporates a channel tap reduction part to select a subset of rows for reduced complexity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional channel estimation algorithm is used, then the channel estimate can be determined, but the calculation complexity is high and a large amount of precalculated values are required
Solution Approach 1:
The channel estimation process is segmented into two distinct stages: first determining channel estimates for individual users using a simplified method, then combining these individual estimates to form the multi-user channel estimate. This segmentation reduces the overall calculation complexity by avoiding the need to process all users simultaneously with complex algorithms.
Solution Approach 2:
The patent extracts and utilizes only the essential components needed for channel estimation - specifically the received pilot symbols and the channel response matrix - while eliminating the need for large amounts of precalculated values and complex processing algorithms. This extraction approach maintains estimation accuracy while reducing computational burden.
2Reliability
If the cyclic prefix length is increased to handle timing misalignment, then timing misalignment can be accommodated, but the transmission efficiency decreases
Solution Approach 1:
The patent changes the approach from increasing the cyclic prefix length to using a correlation-based timing estimation method that works with the existing cyclic prefix structure. By changing the parameter from prefix length to estimation algorithm, the system can handle timing misalignment without sacrificing transmission efficiency.
3Measurement precision
If a full DFT matrix with fundamental period equal to number of sub-carriers is used, then the channel estimate covers all sub-carriers, but the number of calculations increases
Solution Approach 1:
The patent applies partial action by determining channel estimates for individual users separately and then combining them, rather than performing a complete simultaneous estimation for all users. This partial approach reduces the number of calculations while still achieving full channel estimate coverage through the combination step.
Data Source
AI summary
The present invention relates to a receiver for a radio network. The receiver comprises a receiving unit and a channel estimation unit (18). The receiving unit is arranged to receive a number of time domain signals forming a plurality of symbols, each symbol having a cyclic prefix. The channel estimation unit is (18) arranged to determine a channel estimate (hos) in the time domain for a user (u) based on known pilots in the signals received by the receiving unit, and to determine the channel estimate (hos) estimate (hos) for a user (u) using a DFT matrix (V) with a fundamental period related to a number (Nc) of sub-carriers associated to said user (u), wherein the channel estimate (hos) has a length of L taps, L being less that the number (Nc) of sub-carriers associated to said user. The present invention also relates to a method for determining a channel estimate (hos) for a radio channel.