Spectrum Management for LTE WiFi Coexistence
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Solution Overview
Problem
The challenge in wireless communications is to fairly and effectively utilize unlicensed frequency bands, such as the 5 GHz ISM band, among different communication systems like LTE and WiFi, as they have equal access rights, leading to inefficiencies in spectrum resource management, particularly due to unbalanced network loads and interference.
Innovation Solution
A spectrum management apparatus determines the spectrum time validity for LTE systems using unlicensed frequency bands based on spectrum sensing results, allowing for dynamic allocation of usage time periods, ensuring fair access and minimizing interference by coordinating with other systems and sharing information among operators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple communication systems (LTE and WiFi) share unlicensed frequency bands with equal access rights, then spectrum resource utilization increases, but interference and network performance degradation occur
Solution Approach 1:
The patent implements a periodic spectrum access mechanism where LTE systems perform spectrum sensing at regular intervals (e.g., every 10 ms) and allocate transmission opportunities in periodic frames. This periodic structure allows multiple systems to share the unlicensed band systematically, with LTE using discovery reference signals and uplink grants in periodic time slots, while WiFi operates in intervening periods, thereby reducing random interference while maintaining high spectrum utilization
Solution Approach 2:
The patent introduces dynamic spectrum access where the LTE system continuously senses the unlicensed band and adaptively adjusts its transmission parameters based on real-time WiFi detection. When WiFi is detected, LTE dynamically suspends transmission or reduces power; when WiFi is absent, LTE utilizes the full bandwidth. This dynamic behavior optimizes spectrum utilization while minimizing harmful interference to WiFi systems
2Object-affected harmful factors
If LTE systems continuously monitor and adapt to WiFi presence in unlicensed bands, then interference is minimized, but system complexity increases
Solution Approach 1:
The patent employs preliminary spectrum sensing where the LTE system performs WiFi detection in advance before allocating uplink resources. The base station senses the unlicensed band, determines WiFi presence, and pre-adjusts transmission parameters (power, timing, frequency) before LTE transmission begins. This preliminary action prevents interference proactively while simplifying real-time control complexity
Solution Approach 2:
The patent introduces a spectrum management entity that acts as an intermediary between LTE and WiFi systems. This entity centralizes the spectrum sensing and coordination functions, managing the unlicensed band allocation and informing both LTE base stations and WiFi access points of available time-frequency resources. By mediating the interaction, the system reduces individual device complexity while achieving coordinated interference mitigation
3Adaptability or versatility
If spectrum time validity is dynamically determined based on sensing results, then fair access is achieved, but processing time and system overhead increase
Solution Approach 1:
The patent implements preliminary spectrum sensing and validity determination before uplink transmission. The base station senses the unlicensed band, determines spectrum time validity (e.g., 10 ms window), and pre-allocates uplink grants within this valid period. This preliminary determination ensures fair access to WiFi while avoiding real-time processing delays during actual data transmission
Solution Approach 2:
The patent establishes periodic spectrum sensing intervals (e.g., every frame) where spectrum time validity is determined in advance for upcoming transmission opportunities. This periodic structure allows the system to batch process validity determinations rather than continuously processing, reducing overall processing time while maintaining fair periodic access for both LTE and WiFi systems
Data Source
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AI summary
Provided are a device, a spectrum management device and a user equipment used for wireless communication. The spectrum management device used for wireless communication comprises: a determination unit configured to determine, according to a spectrum perception result of an LTE system in the management range of the spectrum management device regarding an unauthorized frequency band, the frequency spectrum aging for the LTE system to use the unauthorized frequency band using different methods.