Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- A fair channel hopping scheme for LoRa Networks with multiple single-channel gatewaysPublication . Figueiredo, Alexandre; Luís, Miguel; ZÚQUETE, ANDRÉLoRa is one of the most prominent LPWAN technologies due to its suitable characteristics for supporting large-scale IoT networks, as it offers long-range communications at low power consumption. The latter is granted mainly because end-nodes transmit directly to the gateways and no energy is spent in multi-hop transmissions. LoRaWAN gateways can successfully receive simultaneous transmissions on multiple channels. However, such gateways can be costly when compared to simpler single-channel LoRa transceivers, and at the same time they are configured to operate with pure-ALOHA, the well-known and fragile channel access scheme used in LoRaWAN. This work presents a fair, control-based channel hopping-based medium access scheme for LoRa networks with multiple single-channel gateways. Compared with the pure-ALOHA used in LoRaWAN, the protocol proposed here achieves higher goodput and fairness levels because each device can choose its most appropriate channel to transmit at a higher rate and spending less energy. Several simulation results considering different network densities and different numbers of single-channel LoRa gateways show that our proposal is able to achieve a packet delivery ratio (PDR) of around 18% for a network size of 2000 end-nodes and one gateway, and a PDR of almost 50% when four LoRa gateways are considered, compared to 2% and 6%, respectively, achieved by the pure-ALOHA approach
- Trading hardware with medium reservation to tackle scalability in low-cost, single-channel LoRa networksPublication . Figueiredo, Alexandre; Luís, Miguel; ZÚQUETE, ANDRÉLoRa is actually one of the most popular LPWAN technologies for IoT applications, due to its low-power and long-range transmissions. A single low-cost, single-channel LoRa Gateway is able to cover a large number of End-Devices spread over a wide area. Gateway diversity is traditionally used to reduce the impact of packet losses: adding more Gateways can increase both delivery ratio and goodput, even when using a pure-ALOHA access policy. However, such solution can be cost-expensive and the adoption of control-based medium access strategies, without violating the duty-cycle constraints, can be, in some situations, a better option. In this letter, we compare the effectiveness of Gateway diversity against a medium access protocol with channel reservation. We evaluate if and in which scenarios, relatively to delivery ratio and goodput, in a single communication channel, it is better to add more Gateways to the system (hardware) or adopt a reservation protocol (software) for tackling the scaling-up of the number of End-Devices.