OFDMA Downlink Scheduling Energy Efficiency via Power and Resource Block Optimization
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Solution Overview
Problem
Current communication systems, particularly in Orthogonal Frequency-Division Multiple Access (OFDMA) networks, fail to optimize energy efficiency in the downlink direction without compromising Quality of Service (QoS), requiring substantial modifications to existing schedulers or resource allocators.
Innovation Solution
A method is introduced that modifies the decisions made by conventional packet schedulers in OFDMA systems by incorporating an energy efficiency post-elaboration module, which evaluates alternative transmission formats and resource allocations to reduce power consumption while maintaining average throughput, using a link layer model to determine optimal power adjustments and resource block allocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional packet schedulers are used to maximize overall cell throughput, then throughput is improved, but energy efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting transmission power and modulation schemes based on channel conditions and queue states. The base station monitors downlink queue lengths and channel quality indicators, then selects appropriate transmission parameters (power levels, MCS indices) from predefined tables to optimize the trade-off between throughput and energy consumption.
Solution Approach 2:
The scheduling system dynamically adapts transmission parameters based on real-time channel conditions and buffer states. The patent implements dynamic power adjustment where the base station continuously monitors queue lengths and channel quality, then dynamically selects transmission power and modulation schemes to maintain throughput while reducing energy consumption when possible.
2Use of energy by moving object
If transmission power is reduced to improve energy efficiency, then power consumption is improved, but Quality of Service deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where user equipment reports channel quality indicators (CQI) to the base station. The base station uses this feedback to adjust transmission parameters, ensuring that power reduction does not compromise QoS. The system continuously monitors and adapts based on feedback to maintain reliable service while optimizing energy consumption.
Solution Approach 2:
The system changes transmission parameters (modulation scheme, coding rate, power level) based on channel conditions and QoS requirements. When channel conditions are good or QoS demands are high, the system uses higher power and more robust modulation. When conditions permit, it reduces power to save energy while maintaining acceptable QoS levels.
3Use of energy by moving object
If existing schedulers are modified substantially to implement energy efficiency, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The patent prepares transmission parameter tables in advance, containing pre-calculated combinations of power levels, modulation schemes, and coding rates optimized for different channel conditions. This preliminary preparation allows the scheduler to make energy-efficient decisions without complex real-time calculations, reducing computational complexity while maintaining energy optimization capabilities.
Data Source
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AI summary
A method of scheduling data transmission of transport blocks in an Orthogonal Frequency-Division Multiple Access communication system, wherein each of the transport blocks is transmitted with a respective transmission format (IMCS) and transmission power in a set of physical resource blocks in the frequency domain. The method identifies the relationship between the transmission power and the block error rate (BLER) for a set of transmission formats (IMCS) / and evaluates alternative transmission formats (IMCS) and different numbers of physical resource blocks for at least one of the transport blocks. Specifically, the method determines a set of alternative transmission formats (IMCS) with different numbers of physical resource blocks, and determines a value being indicative for the total power difference required to transmit the transport block with the alternative transmission format (IMCS) and different number of physical resource blocks, while maintaining a target block error rate (BLERT). The transport block is then transmitted with the alternative transmission format (IMCS) and different number of physical resource blocks if the value indicates that the total transmission power is lower.