Uplink SIC and Non-Orthogonal Coding for Shared Air Interface Resources
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently processing uplink communications from multiple user equipment devices (UEs) on shared air interface resources, where UEs transmit on the same subcarriers and at the same time, leading to interference and difficulty in separating individual transmissions.
Innovation Solution
The implementation of successive interference cancellation (SIC) and non-orthogonal coding techniques, where the base station selects UEs with significantly different uplink receive signal strengths and encodes their data with unique non-orthogonal codes, allowing the base station to separate and process each UE's transmission effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple UEs transmit on shared air interface resources (same subcarriers, same time), then air interface capacity and data rate are improved, but signal interference increases and transmission reliability deteriorates
Solution Approach 1:
The base station segments the combined received signal into individual UE transmissions by applying SIC. The stronger signal is decoded first, subtracted from the combined signal, and the weaker signal is then decoded from the residual. This segmentation enables reliable separation of multiple UEs' transmissions on shared resources.
Solution Approach 2:
The patent changes the coding parameter by using non-orthogonal codes instead of traditional orthogonal codes. This parameter change allows multiple UEs to transmit simultaneously on the same resources while enabling the base station to distinguish their signals through correlation with the known non-orthogonal code sequences.
2Reliability
If traditional orthogonal coding is used for multiple UEs on shared resources, then signal separation is reliable, but air interface capacity and spectral efficiency are limited
Solution Approach 1:
The patent changes the coding parameter from orthogonal codes to non-orthogonal codes. This enables more UEs to share the same air interface resources simultaneously, increasing capacity while maintaining separability through the base station's ability to correlate received signals with known non-orthogonal code sequences and apply SIC.
Solution Approach 2:
The patent converts the harmful effect of non-orthogonal code interference into a benefit. By using non-orthogonal codes with controlled correlation properties and applying SIC, the interference that would normally prevent separation is instead managed systematically, allowing higher capacity while maintaining reliability.
3Productivity
If SIC and non-orthogonal coding are implemented, then processing complexity at the base station increases, but air interface capacity and multi-UE efficiency improve
Solution Approach 1:
The base station performs preliminary actions by pre-storing the non-orthogonal code sequences assigned to each UE. During reception, it correlates the combined signal with these known sequences to identify and decode the stronger signal first, then subtracts it to decode the weaker signal. This preliminary preparation reduces real-time processing complexity.
Data Source
AI summary
A mechanism to help facilitate uplink communication from multiple user equipment devices (UEs) to a base station on shared air interface resources, i.e., with the multiple UEs transmitting to the base station on the same subcarriers and at the same time as each other. The mechanism makes use of successive interference cancellation (SIC) and non-orthogonal coding to help distinguish and separate the UEs' transmissions from each other and thus to help the base station separately process each UE's transmission even though the UEs transmit to the base station on the same air interface resources as each other.