Communication Apparatus Frequency Division Duplex Interference
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Solution Overview
Problem
In areas where older and newer mobile communication systems coexist, the challenge is to improve frequency efficiency and achieve desired cell coverage, particularly in high-frequency bands where signal propagation loss and interference between uplink and downlink signals are significant, making it difficult to maintain effective communication.
Innovation Solution
A communication apparatus that utilizes a frequency division duplex scheme, where the newer system employs a wider frequency band for downlink data channels and a lower frequency band for uplink control channels, allowing the use of a single center gap frequency range for interference suppression, thereby optimizing frequency usage and cell coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a wider frequency band is used for downlink in the newer system, then the data transmission rate is improved, but the cell coverage is degraded due to increased propagation loss at high frequencies
Solution Approach 1:
The patent introduces frequency dimension separation by assigning different frequency ranges to different functions: high frequency (first range) for downlink data channels to achieve high data rates, and low frequency (second range) for uplink control channels to ensure adequate coverage. This dimensional separation in frequency space resolves the contradiction between speed and coverage.
2Reliability
If a frequency division duplex scheme is employed with separate frequency bands for uplink and downlink, then continuous two-way communication is achieved, but a large center gap bandwidth is required to suppress interference, reducing frequency efficiency
Solution Approach 1:
The patent applies local quality by assigning different frequency characteristics to different communication directions and channel types: downlink data uses high frequency for capacity, while uplink control uses low frequency for reliability. This localized optimization of frequency allocation resolves the contradiction between achieving reliable FDD operation and maintaining frequency efficiency.
3Reliability
If transmission power is increased to compensate for propagation loss at high frequencies, then signal quality is improved, but it becomes impractical particularly for user devices
Solution Approach 1:
The patent changes the frequency parameter as a function of communication direction and channel type. By transmitting uplink control channels at lower frequencies with reduced propagation loss, the system achieves adequate signal quality without requiring impractical increases in transmission power, especially for mobile user devices with power constraints.
Data Source
AI summary
A communication apparatus to be used for a newer system employing an FDD scheme in an area where an older system and the newer system coexist. The communication apparatus includes a first communication unit communicating at least a downlink data channel of the newer system using a frequency band belonging to a first frequency range (3.4-3.8 GHz); and a second communication unit communicating at least an uplink control channel of the newer system using a frequency band belonging to a second frequency range (2 GHz band) lower than the first frequency range. The second frequency range is used for uplink and downlink communications in the older system.