Uplink Resource Allocation via Downlink Beacon Geometry
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Solution Overview
Problem
Current wireless communication systems, particularly in UMTS, face challenges in managing uplink intercell interference due to decentralized scheduling in FDD and lack of coordination in TDD systems, which affects coverage and throughput, especially when users are near cell boundaries and cause excessive interference to neighboring cells.
Innovation Solution
The solution exploits the reciprocity of radio channels in TDD and FDD systems by using downlink beacon signals to measure and control uplink interference, allowing UEs to calculate their geometry and report it to the serving Node-B for scheduling, thereby preemptively managing intercell interference without requiring direct communication between Node-Bs or increased UE receiver complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If decentralized scheduling is used in FDD systems, then scheduling speed and responsiveness are improved, but intercell interference control deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where UEs measure downlink beacon signal strengths from neighboring cells and report this information to their serving Node-B. The serving Node-B uses this feedback to calculate geometry values and determine appropriate uplink resource allocations that preemptively control intercell interference while maintaining fast decentralized scheduling.
Solution Approach 2:
The patent applies preliminary action by having UEs measure and report downlink beacon signal strengths before uplink transmissions occur. The serving Node-B uses this advance information to calculate geometry values and allocate uplink resources in a way that prevents excessive intercell interference before it happens, rather than reacting after interference occurs.
2Device complexity
If TDD systems lack coordination between Node-Bs, then system complexity is reduced, but coverage and throughput deteriorate near cell boundaries
Solution Approach 1:
The patent enables self-service by allowing each UE to autonomously measure downlink beacon signal strengths from neighboring cells and calculate its own geometry value. The serving Node-B uses this self-reported information to make scheduling decisions, eliminating the need for complex coordination between Node-Bs while maintaining reliable coverage and throughput through geometry-based resource allocation.
Solution Approach 2:
The patent changes the parameter used for scheduling decisions from traditional signal strength measurements to geometry values derived from downlink beacon signal strengths. This parameter change allows the system to maintain simple decentralized operation while improving coverage and throughput near cell boundaries by accounting for the spatial relationship between UEs and neighboring cells.
3Productivity
If UEs near cell boundaries transmit at high power, then their own throughput is improved, but intercell interference to neighboring cells increases
Solution Approach 1:
The patent applies local quality by allocating uplink resources based on individual UE geometry values. Each UE receives a tailored resource allocation that reflects its specific spatial relationship with neighboring cells, rather than applying uniform power control. This allows UEs near cell boundaries to transmit at appropriately reduced power levels to minimize intercell interference while maintaining adequate throughput.
Solution Approach 2:
The patent implements preliminary anti-action by preemptively reducing uplink resource allocations for UEs with low geometry values (indicating proximity to cell boundaries) before they can cause excessive intercell interference. The serving Node-B calculates geometry values and adjusts resource allocations in advance to counteract the potential harmful effect of high-power transmissions from boundary UEs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces intercell interference, maintains system coverage, and enhances system capacity by scheduling uplink resources based on user geometry, while maintaining the benefits of distributed scheduling architectures such as faster scheduling and lower latency.
Implementation Method 1
The solution exploits the reciprocity of radio channels in TDD and FDD systems by using downlink beacon signals to measure and control uplink interference
Data Source
AI summary
Embodiments of the present invention exploit the reciprocity of radio channels in TDD, and longer-term correlation between average uplink and downlink path losses in FDD wireless communication systems to enable distributed schedulers in an enhanced uplink system to allocate uplink transmission resources while preemptively managing intercell interference levels. Each cell's base station transmits a downlink reference signal at a known transmission power level. A mobile station monitors the received signal strength of the downlink reference signals from multiple base stations. The transmitted and received signal strength levels can be used by the mobile station to estimate the amount of intercell interference that the mobile station's uplink transmissions cause, and the mobile station's uplink transmission parameters are adjusted accordingly. In further embodiments, the received reference signal power levels, or values derived therefrom, are transmitted by the mobile station to its serving base station, where a scheduling algorithm uses the information to adjust one or more transmission parameters relating to a grant of uplink transmission resources to the UE, thereby controlling the intercell interference generated by the mobile station's uplink transmissions.