Radio Communication Apparatus Adaptive Frequency Hopping
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Solution Overview
Problem
Conventional frequency hopping methods in the ISM band, such as those using the 2.4 GHz band, face interference issues due to the time required to adapt to optimal hopping patterns, leading to potential communication quality degradation and interference during changes in the radio environment.
Innovation Solution
A radio communication apparatus employing an FHSS method with intermittent receiving operations and a predetermined hopping pattern, where spare carrier frequencies are recycled and prioritized, and the number of cycle frames and hopping carrier frequencies have a prime relationship to quickly adapt to interference and maintain communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frequency hopping method is used to avoid radio wave interference, then resistance to disturbance is improved, but interference may still occur when a carrier frequency overlaps with a continuous interference source
Solution Approach 1:
The hopping pattern is dynamically changed based on detected interference conditions. When interference is detected at a specific carrier frequency, the system modifies the hopping pattern to exclude that frequency, transforming from a static predetermined pattern to a dynamic adaptive pattern that responds to environmental changes.
Solution Approach 2:
The system changes the parameters of the hopping pattern (specifically the carrier frequency selection) based on detected interference conditions. By modifying which carrier frequencies are included in the hopping sequence, the system adapts to avoid continuous interference sources while maintaining the frequency hopping mechanism's disturbance resistance.
2Object-affected harmful factors
If an adaptive frequency hopping method is used to change hopping pattern to avoid interference, then interference avoidance is improved, but a certain time is required until change to optimum hopping pattern is carried out after start of communication
Solution Approach 1:
The system performs preliminary detection of interference conditions at the start of communication and immediately adjusts the hopping pattern before significant interference can occur. By detecting and responding to interference conditions early in the communication process, the system minimizes the time loss associated with pattern changes.
3Object-affected harmful factors
If carrier frequencies are removed as spare carriers from hopping pattern due to interference, then interference avoidance is improved, but usable spare carriers are exhausted when same number of carriers as spare carriers are exchanged
Solution Approach 1:
When a carrier frequency is removed from the hopping pattern due to interference, it is added to the spare carrier pool. When the spare carrier pool is exhausted, the system can recover previously removed carriers by重新adding them to the hopping pattern once interference conditions change, thus recycling carrier frequencies and maintaining adaptability.
Data Source
AI summary
A radio communication apparatus and method employs frequency hopping in a predetermined pattern based on a hopping carrier table. An intermittent receiving section activates a carrier frequency designating section every constant cycle to give a command for receiving the control channels of opposing radio base stations. In the case in which a hopping order in a hopping carrier table is skipped by n to carry out switching every intermittent receiving cycle in an intermittent receiving operation, an intermittent receiving cycle is set in such a manner that the n and a total number m of hopping carrier frequencies in the hopping carrier table have a prime relationship with each other. The electric field strength of a carrier frequency in a spare carrier list is measured by the intermittent receiving operation and an interference counter of a spare carrier is increased or decreased corresponding to a frequency at which the electric field strength exceeds or does not exceed a predetermined threshold. A carrier frequency deleted from a hopping pattern and placed in the spare carrier list is set to have the worst value as the initialized value of its interference counter.