Cell-Specific Scrambling for Wireless Signal Reliability
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Solution Overview
Problem
Existing wireless communication networks face challenges in improving the Signal to Noise Ratio (SNR) due to inter-cell interference, as conventional block repetition methods do not effectively differentiate between wanted and interfering signals, leading to less gain in carrier-to-interference ratio when interference is present.
Innovation Solution
Implementing cell-specific scrambling and de-scrambling techniques, where each cell uses a unique scrambling code for its transmissions, allowing wanted signals to be coherently combined while interfering signals from other cells are non-coherently combined, thereby reducing the impact of inter-cell interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block repetition is used to improve SNR, then signal reliability is improved, but inter-cell interference is not effectively reduced
Solution Approach 1:
The patent applies cell-specific scrambling codes to differentiate between signals from different cells. Each cell uses a unique scrambling code, which allows the receiving node to identify and coherently combine wanted signals while non-coherently combining interfering signals from other cells. This local differentiation resolves the contradiction by maintaining signal reliability through coherent combining of desired signals while reducing inter-cell interference through non-coherent combining of scrambled interfering signals.
2Area of stationary object
If conventional block repetition is applied, then transmission coverage is extended, but carrier-to-interference ratio gain is limited
Solution Approach 1:
The patent changes the scrambling code parameter for each cell to improve carrier-to-interference ratio. By assigning different scrambling codes to different cells, the system enables the receiving node to distinguish between wanted and interfering signals. This parameter change allows coherent combining of wanted signals (maintaining signal strength for coverage) while non-coherently combining interfering signals (reducing their impact), thereby achieving both extended transmission coverage and improved carrier-to-interference ratio.
Data Source
AI summary
A sending node sends information to a receiving node. Said nodes are comprised in a wireless communication network. Communication between said nodes is associated with a first cell. The sending node obtains predefined scrambling for scrambling the information and which predefined scrambling is specific for the first cell. The receiving node correspondingly obtains de-scrambling. The sending node sends, to the receiving node, the information repeatedly a certain number of times, wherein each time the information is sent it is scrambled differently based on the obtained scrambling. Each time the information is received by the receiving node it is de-scrambled differently based on the obtained de-scrambling.