FDD Front-End Uplink Power for SAR-Compliant Coverage
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Solution Overview
Problem
Cellular user equipment (UE) is limited by Specific Absorption Rate (SAR) regulations, restricting uplink power in FDD systems, leading to potential loss of communication at the cell edge or indoors, where link quality is at risk.
Innovation Solution
Implementing a front end system with a power amplifier and low noise amplifier, along with a duplexer and antenna switch module, to enable high power uplink transmission at a finite duty cycle and within SAR limits, using frequency division duplexing to increase data rates and maintain stable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uplink power is increased to maintain stable communication at cell edge or indoors, then connection stability is improved, but SAR regulatory limits are exceeded
Solution Approach 1:
The patent applies periodic action by transmitting uplink signals at high power only during specific time intervals (uplink slots) while remaining silent during downlink slots. This duty-cycled transmission pattern allows the system to achieve higher average transmit power for improved connection stability while maintaining compliance with SAR regulatory limits through temporal distribution of power transmission.
2Duration of action of stationary object
If continuous transmission is used in FDD systems, then communication coverage is maintained, but uplink power must be limited below SAR thresholds
Solution Approach 1:
The system transitions from continuous low-power transmission to periodic high-power transmission by utilizing the inherent time-division structure of FDD. Uplink transmission occurs in periodic bursts during allocated uplink slots at higher power levels, while downlink slots remain silent for uplink transmission. This periodic pattern extends communication coverage through higher peak power while maintaining SAR compliance through average power control.
3Productivity
If higher uplink power is transmitted to prevent call drops, then data rate and connection stability are improved, but regulatory power limits are exceeded
Solution Approach 1:
The patent implements periodic high-power transmission during uplink slots to achieve higher data rates and prevent call drops, while maintaining regulatory compliance through average power control. The duty cycle inherent in FDD time-division structure allows peak power to exceed traditional limits while keeping average power within SAR thresholds, thereby improving productivity without violating power limit regulations.
Solution Approach 2:
The system changes the power transmission parameter from continuous low-power mode to periodic high-power mode. By adjusting the temporal distribution of power transmission and utilizing the duty cycle of FDD, the system achieves higher effective data rates while maintaining compliance with average power limits through parameter optimization.
Data Source
AI summary
Systems and methods for high power uplink transmission are disclosed. In one aspect, a mobile device includes an antenna configured to transmit radio frequency signals to a base station via an uplink and receive radio frequency signals from the base station via a downlink and a front end system coupled to the antenna. The front end system is configured to transmit and receive the radio frequency signals from the antenna, and duplex the radio frequency signals via frequency division duplexing. The front end system is further configured to transmit data on the uplink at a first power level that is higher than a predetermined level and at a finite duty cycle.