Orthogonal Code Interference Reduction in Wireless Systems
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Solution Overview
Problem
Inter-cell interference is a significant limiting factor in wireless communication systems, particularly for devices near the edge of cells where another cell's transmission can reach, especially in systems with a frequency reuse factor of one, which affects system performance and capacity.
Innovation Solution
The method involves encoding resource blocks from adjacent cells with different orthogonal codes from a family of orthogonal codes, allowing these encoded blocks to be transmitted overlapping in time and frequency, thereby reducing interference without restricting resource scheduling or transmit power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency reuse factor of one is used to increase system capacity, then more resource blocks can be scheduled, but inter-cell interference increases significantly
Solution Approach 1:
The resource blocks are segmented by applying different orthogonal codes from a code family to different cells. This segmentation allows the same frequency resources to be divided into orthogonal channels, enabling frequency reuse factor of one while maintaining signal separation between cells and reducing inter-cell interference.
Solution Approach 2:
The patent changes the coding parameter by applying different orthogonal codes to different cells transmitting on the same frequency. This parameter change transforms the interference problem into an orthogonal signaling problem, allowing simultaneous transmissions without interference while achieving frequency reuse factor of one.
2Object-affected harmful factors
If orthogonal codes are applied to resource blocks in adjacent cells, then inter-cell interference is reduced, but device complexity increases due to encoding requirements
Solution Approach 1:
The orthogonal codes are applied in advance to the resource blocks before transmission. This preliminary encoding action prepares the signals for orthogonal multiplexing, allowing the interference reduction to work automatically during transmission without requiring complex real-time processing at the transmitter.
Solution Approach 2:
The orthogonal codes act as an intermediary between the resource blocks and the transmission medium. These codes provide a mathematical framework that separates the signals from different cells, reducing interference while maintaining a relatively simple encoding structure that can be efficiently implemented.
Data Source
AI summary
A wireless communication system serves a first wireless device with a first access node using a frequency band and serves a second wireless device in an adjacent cell with a second access node that uses the same frequency band. The communication of a first resource block is scheduled between the first wireless device and the first access node. The communication of a second resource block between the second wireless device and the second access node is also scheduled. The scheduling of the first resource block and the second resource block correspond in time and frequency. The first resource block is encoded with a first orthogonal code from a family of orthogonal codes. The second resource block is encoded with a second orthogonal code from the family of orthogonal codes. After encoding, the first resource block and the second resource blocks are transmitted using the frequency band.