Wireless Transmitter Pre-Processing for ISI Reduction
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Solution Overview
Problem
High Inter-Symbol Interference (ISI) in wireless communication systems degrades performance and increases complexity in receiving devices, particularly when channel memory is long, leading to costly and resource-intensive solutions.
Innovation Solution
A transmitting device with a processor that determines pre-processing coefficients for a pre-processor structure based on the channel response, allowing for pre-processing of data before transmission, which reduces ISI and maintains low complexity in receiving devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel equalisation using Viterbi algorithm is employed to reduce ISI, then receiving device performance is improved, but device complexity increases exponentially with channel memory length
Solution Approach 1:
The patent applies preliminary action by performing pre-processing of the transmitted signal before it enters the channel. The pre-processor modifies the signal characteristics in advance to counteract the expected ISI effects, so that the receiving device does not need to perform complex equalisation operations. This shifts the computational burden from the receiver to the transmitter, resolving the contradiction between performance and complexity at the receiving device.
2Reliability
If complex pre-processing algorithms are introduced to improve channel performance, then transmission quality is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies local quality by designing a pre-processor with specific local characteristics that are tailored to the channel conditions. The pre-processing coefficients are determined based on the channel impulse response, creating a localized adaptation to the specific channel characteristics rather than using a general complex algorithm. This provides effective channel compensation with controlled complexity.
3Manufacturing precision
If ISI is reduced through traditional equalisation methods, then minimum Euclidean distance is improved, but receiving device complexity increases
Solution Approach 1:
The patent applies inversion by reversing the traditional approach: instead of having the receiving device perform complex equalisation to correct ISI, the transmitting device performs pre-processing to prevent ISI from degrading the signal. This inverts the location and nature of the processing, maintaining minimum Euclidean distance while keeping the receiving device simple.
Data Source
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AI summary
Transmitting device (110) for a wireless communication system (100) and method (400) therein for transmitting data. The transmitting device (110) comprises a processor (520), configured to: obtain a channel response (h); determine pre-processing coefficients (g0, g1, g2) of a pre-processor structure, based on the obtained channel response (h); and pre- process the data, based on the pre-processor structure and the determined pre-processing coefficients (g0, g1, g2). The transmitting device (110) comprises a transmitter (530), configured to transmit the pre-processed data.