Buffer management policies for BLE-based multi-hop communication
Arun Soman · TU/e Research Portal · 2014
Bluetooth Low Energy (BLE) has gained a lot of popularity since its introduction in the Bluetooth Core 4.0 standards, mainly due to its compatibility with modern smartphones. BLE provides low energy and low cost solution for low data rate wireless communication. To reduce complexity, BLE supports only peer-to-peer, master-slave communication. This proves to be a roadblock in its application in many moderately large wireless sensor network (WSNs) applications where line of sight communication is not sufficient. We tackle this problem by introducing multi-hop communication over BLE. This work proposes a novel routing mechanism and data transfer functionality over BLE radio and link layer, which is tested with an actual implementation on custom hardware from IMEC. The data transfer in BLE over multiple hops is essentially a series of connection events where each connection event can transfer large amount of data to its neighboring node resulting in each node storing large amount of data. But if complete buffer space is provided to a single node in a connection event, the other nodes willing to send data through the same relay node will not get buffer space till all the data from previous node is forwarded and the relay node has empty buffer space. This may cause starvation of the nodes. This leads to a need of buffer management strategy in BLE multi-hop networks. We introduce two buffer allocation strategies in this work namely ‘1-by-k buffer allocation mechanism’and ‘buffer allocation based on average number of connections’. The strategies moderate the factor (k and average number of connections) deciding the fraction of the buffer space which is allocated to a requesting node. These proposed strategies are tested with a high level simulation in MATLAB for their performance in non-mobile networks. The simulation results show that ‘buffer allocation based on average number of connections’method performs better in the tested scenarios. Buffer Management Policies for BLE-based Multi-hop Communication iii