Block-wise CDMA Overlay on TDMA for Coverage and Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio access technologies face challenges in increasing coverage while maintaining channel capacity, particularly in scenarios where channel variations are slow or non-existent, as conventional techniques like block repetition improve SNR but reduce channel capacity.
Innovation Solution
A wireless apparatus and method that utilize a block-wise Code Division Multiple Access (CDMA) scheme overlaid on a Time Division Multiple Access (TDMA) structure, involving a processor to obtain code bits, generate baseband signals, divide them into blocks, repeat and multiply these blocks using orthogonal code words, and transmit them to maintain capacity while enhancing coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block repetition is used to increase coverage, then SNR is improved, but channel capacity is reduced
Solution Approach 1:
The baseband signal is divided into multiple blocks, each block being repeated N times and multiplied by orthogonal code words. This segmentation allows the system to maintain channel capacity by processing different blocks independently while still achieving coverage improvement through coherent combining at the receiver.
Solution Approach 2:
The patent introduces a code domain dimension by multiplying repeated blocks with orthogonal code words. This adds a new dimension to the signal structure, allowing multiple users to share the same physical resource without interference, thereby maintaining capacity while improving coverage.
2Productivity
If multiple users share the same physical resource, then resource utilization is improved, but interference between users increases
Solution Approach 1:
By introducing orthogonal code words in the code domain, the patent creates an additional dimension for user separation. Multiple users can now share the same time-frequency resource without interference because their signals are orthogonalized through the code domain, effectively resolving the trade-off between resource utilization and interference.
Solution Approach 2:
The system changes the signal parameters by applying orthogonal code multiplication to repeated blocks. This parameter transformation ensures that signals from different users remain orthogonal even when sharing the same physical resource, eliminating interference while maximizing resource utilization.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A wireless apparatus (e.g., wireless access node, wireless device) and a method are described herein that use a block -wise Code Division Multiple Access (CDMA) scheme overlaid to a Time Division Multiple Access (TDMA) structure to communicate over a physical channel with another wireless apparatus (e.g., wireless device, wireless access node).