Base Station Uplink Scheduling for OMA-NOMA Interference Control
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Solution Overview
Problem
In communication systems where both Orthogonal Multiple Access (OMA) and Non-Orthogonal Multiple Access (NOMA) coexist, there is a risk of degraded communication quality for OMA due to interference from NOMA, especially when the number of NOMA transmissions exceeds the interference removal capability of the reception device.
Innovation Solution
A communication system that integrates non-contention based (OMA) and contention based (NOMA) multiple access methods, utilizing Symbol Level Interference Cancellation (SLIC) and other interference cancellation techniques at the base station to detect and separate overlapping uplink data signals, allowing for simultaneous data transmission without requiring SR or UL Grant reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminal apparatuses transmit uplink data simultaneously using contention-based NOMA, then the transmission efficiency and data rate are improved, but the communication quality for OMA users is degraded due to interference
Solution Approach 1:
The patent segments the uplink transmission resources by introducing a grant-free transmission region separate from the traditional grant-based region. This segmentation allows NOMA users to transmit in the grant-free region while OMA users operate in the grant-based region, reducing mutual interference. The base station also segments the received signals by identifying and separately processing NOMA and OMA signals using different detection methods.
Solution Approach 2:
The base station acts as an intermediary that applies interference cancellation techniques (such as SIC - Successive Interference Cancellation) to remove NOMA signals from the received composite signal before detecting OMA signals. This intermediary processing step protects OMA users from NOMA interference while maintaining NOMA transmission benefits.
2Quantity of substance
If the number of NOMA transmissions increases to support more terminal apparatuses, then the system capacity is improved, but the interference removal capability of the reception device is exceeded, causing detection failures
Solution Approach 1:
The base station extracts and removes NOMA signals from the composite received signal using interference cancellation techniques before detecting OMA signals. This extraction process isolates the OMA signals from NOMA interference, maintaining detection accuracy even when multiple NOMA users are present. The base station takes out the interfering NOMA components systematically.
Solution Approach 2:
The base station performs preliminary interference cancellation by detecting and removing NOMA signals before proceeding with OMA signal detection. This preliminary action prevents NOMA interference from degrading OMA detection accuracy, enabling the system to support more NOMA users without sacrificing OMA communication quality.
3Reliability
If grant-based OMA transmission is used to ensure reliable communication, then the communication quality is maintained, but the overhead from control information increases
Solution Approach 1:
The patent introduces dynamic transmission mode selection where terminal apparatuses can switch between grant-based transmission and grant-free transmission based on their needs. Small data transmissions use grant-free mode to reduce overhead, while large or critical data transmissions use grant-based mode for reliability. This dynamic approach optimizes the trade-off between overhead and reliability.
Solution Approach 2:
The system changes the transmission parameters by introducing grant-free transmission regions with different characteristics from traditional grant-based regions. In grant-free regions, terminals transmit without receiving UL Grants, eliminating SR and BSR overhead for small data. The base station configures parameters such as transmission power, resource allocation, and modulation schemes differently for grant-free and grant-based transmissions.
Data Source
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Figure 3(A)~3(C)
AI summary
Provided are a base station apparatus, a terminal apparatus, and a communication method, in a case that uplink data transmission based on orthogonal multiple access and uplink data transmission based on non-orthogonal multiple access coexist in a cell in which many terminal apparatuses present, capable of maintaining a prescribed communication quality for the uplink data. The base station apparatus for communicating with a terminal apparatus configured to support contention based access and non-contention based access transmits, in a case that an uplink data channel received in a non-contention based manner occurs in a subframe including the contention based access region, a contention based transmission configuration change notification with respect to a subframe configured to receive the uplink data channel.