Load Estimation for OFDMA Resource Allocation
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Solution Overview
Problem
Existing load estimation techniques in communications devices, particularly for OFDMA systems, face challenges in accurately estimating the resource requirements for Quality of Service (QoS) and managing interference, which is crucial for admission control, congestion control, and load balancing, especially in WCDMA systems where interference-based resource allocation complicates the estimation process.
Innovation Solution
A communications apparatus and method that includes a transceiver circuit, scheduler, and load estimator to estimate resource blocks required for QoS by using measurement data from radio conditions, spectral efficiency, and bit rates, employing equations such as ρ=a_1KRreqω_ and Δρ=RreqK(a_ω_) to determine load and load increase for existing and new bearers, respectively, facilitating accurate resource allocation and admission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interference-based resource allocation is used in WCDMA systems, then power levels can be adjusted to maintain quality, but the estimation process becomes iterative and complex
Solution Approach 1:
The patent extracts the interference calculation from the iterative process by directly computing the interference contribution of each bearer based on allocated power levels and channel conditions, eliminating the need for repeated iterations while maintaining accuracy in load estimation
Solution Approach 2:
The patent performs preliminary calculation of interference levels and power requirements before final admission decisions are made, allowing the system to pre-determine the impact of new bearers on existing services without requiring iterative adjustments during the decision process
2Ease of operation
If average block requirement is used for load estimation, then admission control is simplified, but accuracy in estimating actual resource needs is reduced
Solution Approach 1:
The patent transitions from static average block requirements to dynamic load estimation that adapts to current radio conditions by using real-time measurements of channel quality, spectral efficiency, and actual resource block allocations, allowing the system to maintain simplicity while improving accuracy
Solution Approach 2:
The patent incorporates feedback from actual resource usage and channel conditions into the load estimation process, using measured data from the radio interface to continuously refine estimates of required resources rather than relying on pre-stored average values
3Reliability
If iterative interference convergence is performed, then quality of all bearers is optimized, but the process time increases and bearers may be dropped
Solution Approach 1:
The patent performs preliminary assessment of interference impact using closed-form calculations based on allocated power and channel state information, allowing the system to determine whether quality requirements can be met without initiating time-consuming iterative convergence processes
Solution Approach 2:
The patent preemptively calculates and compensates for interference effects by adjusting power allocation and resource assignment before admitting new bearers, preventing quality degradation that would otherwise require iterative correction or result in bearer drops
Data Source
AI summary
An OFDM based communications system is provided, in which a scheduler is configured to estimate the load of existing bearers and the load increase that will arise from a new requested bearer if that bearer is accepted. Several techniques are described for estimating these loads and their advantages and disadvantages are also discussed. Estimators are also provided that can estimate the loads from a previous estimate and current load conditions.