# Achieving Max-Min Throughput in LoRa Networks

## TL;DR

This paper proposes a novel resource allocation framework for LoRa networks that maximizes the minimum throughput among users, addressing fairness and interference challenges with a tractable analytical model and an iterative balancing method.

## Contribution

It introduces a new analytical model for LoRa networks considering fading and interference, and develops an iterative method for fair resource allocation based on average channel statistics.

## Key findings

- Significant improvement in cell-edge throughput.
- Effective mitigation of near-far fairness problem.
- Accurate closed-form success probability formula.

## Abstract

With growing popularity, LoRa networks are pivotally enabling Long Range connectivity to low-cost and power-constrained user equipments (UEs). Due to its wide coverage area, a critical issue is to effectively allocate wireless resources to support potentially massive UEs in the cell while resolving the prominent near-far fairness problem for cell-edge UEs, which is challenging to address due to the lack of tractable analytical model for the LoRa network and its practical requirement for low-complexity and low-overhead design. To achieve massive connectivity with fairness, we investigate the problem of maximizing the minimum throughput of all UEs in the LoRa network, by jointly designing high-level policies of spreading factor (SF) allocation, power control, and duty cycle adjustment based only on average channel statistics and spatial UE distribution. By leveraging on the Poisson rain model along with tailored modifications to our considered LoRa network, we are able to account for channel fading, aggregate interference and accurate packet overlapping, and still obtain a tractable and yet accurate closed-form formula for the packet success probability and hence throughput. We further propose an iterative balancing (IB) method to allocate the SFs in the cell such that the overall max-min throughput can be achieved within the considered time period and cell area. Numerical results show that the proposed scheme with optimized design greatly alleviates the near-far fairness issue, and significantly improves the cell-edge throughput.