Uplink Power Management and Distributed Scheduling for Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in managing power and scheduling for uplink transmissions, leading to excessive inter-sector interference, unfair data rate distribution, and reduced throughput due to unreliable carrier-to-interference ratio estimation.
Innovation Solution
A power management and distributed scheduling scheme that limits transmission power for mobile devices to prevent excessive interference, allowing for dynamic data rate utilization and accurate interference estimation, thereby enabling fair and efficient Quality of Service support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher power uplink transmissions are used to increase data rate, then data rate is improved, but inter-sector interference increases excessively
Solution Approach 1:
The patent implements dynamic power control where transmission power is adjusted based on real-time channel conditions and interference levels. The system dynamically selects modulation and coding schemes (AMCS) that adapt to current network conditions, allowing mobiles to use higher power when needed while avoiding excessive interference through intelligent power management algorithms that consider both data rate requirements and interference impact on neighboring sectors.
Solution Approach 2:
The system changes multiple parameters simultaneously including power level, modulation scheme, and coding rate based on channel conditions. By varying these parameters dynamically, the system achieves higher data rates when channel conditions permit while controlling interference through coordinated parameter adjustment across multiple mobiles in a sector.
2Object-generated harmful factors
If time division multiplexing is used to stagger transmissions, then inter-sector interference is reduced, but system complexity increases
Solution Approach 1:
The patent implements a distributed scheduling approach where each mobile device autonomously determines its transmission timing and power level based on local channel conditions and received control information. The base station provides guidance through control channels, but individual mobiles make scheduling decisions independently, eliminating the need for complex centralized coordination while still achieving interference control through distributed time-slot allocation.
3Device complexity
If a fixed ROT target is used for all base stations, then simplicity is maintained, but fairness in uplink transmissions deteriorates
Solution Approach 1:
The system transitions from a uniform fixed ROT target to location-specific and condition-specific power targets. Each mobile receives customized power control instructions based on its geographic location, channel conditions, and the current state of neighboring sectors. This localizes the quality of service parameters to match actual network conditions, achieving fairness while maintaining manageable complexity through distributed decision-making.
4Reliability
If large interference margin is used to avoid channel errors, then reliability is improved, but capacity of uplink and downlink decreases
Solution Approach 1:
The patent implements dynamic interference margin adjustment where the margin is not fixed but varies based on real-time channel conditions, signal-to-interference ratio, and network load. When channel conditions are favorable and interference is low, the system uses smaller margins to maximize capacity. When conditions deteriorate, the margin increases automatically to maintain reliability, thus optimizing the trade-off between these two parameters throughout operation.
Data Source
AI summary
To schedule uplink transmission time slots for a collection of mobile. communication devices, a set of base station target interference patterns is associated with base stations. A time slot target interference pattern is assigned for each time slot and it repeats after several time slots. The time slot target interference pattern in a given time slot specifies the interference allowed by each time slot to a given base station by any single mobile. A priority index may be determined for each time slot for each mobile associated with the particular base station. The priority index may be based, in part, on a determined correlation between the time-slot target interference patterns and a potential interference profile of a mobile to which a time slot is to be allocated. A mobile's throughput requirement, the throughput already received over a specified past duration, the system fairness requirement, as well as the amount of data available for transmission are also used for evaluating the priority index.