Adaptive configuration of lora networks for dense IoT deployments

Abstract

Large-scale Internet of Things (IoT) deployments demand long-range wireless communications, especially in urban and metropolitan areas. LoRa is one of the most promising technologies in this context due to its simplicity and flexibility. Indeed, deploying LoRa networks in dense IoT scenarios must achieve two main goals: efficient communications among a large number of devices and resilience against dynamic channel conditions due to demanding environmental settings (e.g., the presence of many buildings). This work investigates adaptive mechanisms to configure the communication parameters of LoRa networks in dense IoT scenarios. To this end, we develop FLoRa, an open-source framework for end-to-end LoRa simulations in OMNeT++. We then implement and evaluate the Adaptive Data Rate (ADR) mechanism built into LoRa to dynamically manage link parameters for scalable and efficient network operations. Extensive simulations show that ADR is effective in increasing the network delivery ratio under stable channel conditions, while keeping the energy consumption low. Our results also show that the performance of ADR is severely affected by a highly-varying wireless channel. We thereby propose an improved version of the original ADR mechanism to cope with variable channel conditions. Our proposed solution significantly increases both the reliability and the energy efficiency of communications over a noisy channel, almost irrespective of the network size. Finally, we show that the delivery ratio of very dense networks can be further improved by using a network-aware approach, wherein the link parameters are configured based on the global knowledge of the network.

How Agile is the Adaptive Data Rate Mechanism of LoRaWAN?

“…To evaluate the ADR mechanism, we simulated networks consisting of a gateway with a varying number of randomly distributed EDs that transmit one packet every ten minutes on average. An urban scenario with the same path loss model as used by earlier works [9], [6] is assumed. The EDs are tuned to use the default three central carrier frequencies in the g1 sub-band of the European sub-GHz ISM band, which is subject to a 1% duty cycle limit.…”

“…Therefore, we make a timely contribution in this paper by evaluating the performance of the ADR mechanism as a first step towards exposing different limitations and improving the underlying technique. Unlike most other studies [4], [5], [6], [7], [8] that focus on network-wide performance metrics related to scalability, reliability, fairness, and throughput, we focus on performance that the individual EDs receive while running the ADR mechanism. We provide an in-depth study of the agility of the ADR mechanism in adapting the communication settings of EDs in response to link changes.…”

A Thorough Study of LoRaWAN Performance Under Different Parameter Settings

“…The authors in [19], [20] target the original ADR algorithm proposed by [4], suggesting possible ameliorations. Generally, the modified algorithms yield an increase of network scalability, fairness among nodes, packet delivery ratio and robustness to variable channel conditions.…”

A Novel Rate and Channel Control Scheme Based on Data Extraction Rate for LoRa Networks

“…The short-term DER is defined as the ratio of successfully received messages to transmitted messages in a short period [6]. The details of mechanism are described in Algorithm 1 (line [7][8][9][10][11][12][13][14][15][16][17] In order to obtain the short-term DER, the estimation window is defined in advance. It is the fixed number of received packets by LoRa network server.…”

“…Although most of the existing studies focus on evaluating the performance of LoRa network as well as coverage and scalability [4]- [8], the impact of Adaptive Data Rate (ADR) scheme is not thoroughly investigated. Moreover, several related works propose some methods to control the transmission parameters with different objectives [9]- [13]. To the best of our knowledge, the existing works focus on either data rate allocation or channel selection control.…”