Mixed Numerology Frame Structure for mm-Wave NR
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Solution Overview
Problem
New Radio (NR) operation in millimeter-wave frequency bands faces challenges such as higher phase noise, larger propagation loss, and strong power spectral density regulatory requirements, which affect the design of physical channels and signal transmission.
Innovation Solution
A mixed numerology frame structure is implemented, allowing different subcarrier spacings for control and data channels within a bandwidth part (BWP), with smaller spacings for control channels to improve link budget and larger spacings for data channels to combat phase noise, while maintaining scheduling granularity and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single numerology with uniform subcarrier spacing is used for all channels in a bandwidth part, then the system structure is simple and scheduling is straightforward, but link performance deteriorates in mm-wave bands due to phase noise and propagation losses
Solution Approach 1:
The bandwidth part is divided into multiple numerology groups, where each group can use a different subcarrier spacing configuration. Control channels use one numerology while data channels use another, allowing optimization for their respective requirements without affecting the entire system structure.
Solution Approach 2:
Different subcarrier spacings are assigned to different channel types (control vs. data) within the same bandwidth part. This local differentiation allows control channels to use smaller spacing for better coverage while data channels use larger spacing to combat phase noise, optimizing performance locally for each channel type.
2Reliability
If smaller subcarrier spacing is used for control channels, then link budget and cell coverage are improved, but phase noise becomes more severe for data channels
Solution Approach 1:
The system segments channels into control and data categories, assigning appropriate subcarrier spacings to each segment. Control channels receive smaller spacing for coverage optimization, while data channels receive larger spacing for phase noise mitigation.
Solution Approach 2:
The subcarrier spacing parameter is changed based on channel type and operational requirements. The system dynamically selects from multiple numerology options (15, 30, 60, 120 kHz) to match the specific needs of control or data channels in mm-wave conditions.
3Reliability
If different subcarrier spacings are used for control and data channels, then link performance is optimized for each channel type, but scheduling granularity and signaling overhead become more complex
Solution Approach 1:
The scheduling system is segmented to handle different numerologies independently within the same bandwidth part. Each numerology group can be scheduled separately, allowing the system to manage complexity by treating each numerology as an independent resource pool while maintaining overall coordination.
Solution Approach 2:
The framework is designed to support multiple numerologies simultaneously within a single bandwidth part, making the system universal enough to handle diverse channel requirements. The scheduling mechanism can adapt to different numerology combinations without requiring separate system designs.
Data Source
AI summary
A method, system and apparatus are disclosed. According to one or more embodiments, a network node configured to communicate with a wireless device is provided. The network node includes processing circuitry configured to dynamically indicate a mixed numerology to the wireless device for implementation where the mixed numerology corresponds to a first numerology for a data channel and a second numerology for a control channel, the first numerology being different from the second numerology.