Parallel inclusive communication for connecting heterogeneous IoT devices at the edge

Abstract

WiFi and Bluetooth Low Energy (BLE) are widely used in Internet of Things (IoT) devices. Since WiFi and BLE work within the overlapped ISM 2.4 GHz band, they will interfere with each other. Existing approaches have demonstrated their effectiveness in mitigating the interference. However, further performance improvement has been hampered by the design goal of exclusive communication of WiFi or BLE, which only allows one WiFi or BLE device to transmit packets at any specific time slot on the overlapped channel within the communication range. In this paper, we explore a new communication method, called Parallel Inclusive Communication (PIC), which leverages the unique modulation schemes of WiFi and BLE for parallel inclusive bi-directional transmission of both WiFi and BLE data at the same time within the overlapped channel. In this communication system, the PIC gateway is designed upon the IEEE 802.11g and 802.15.1 frameworks while the WiFi and BLE clients are commercial off-the-shelf devices. PIC achieves similar data rates for these parallel WiFi and BLE communications as if WiFi and BLE are communicating separately. PIC's system architecture naturally fits at the edge of the Internet, which is an optimal site for concurrently collecting (or disseminating) data from (or to) an exponentially increasing number of IoT devices that are using WiFi or BLE. We conducted extensive evaluations under four real-world scenarios. Results show that compared with existing approaches, PIC can significantly i) increase the packet reception ratios by 183%; ii) reduce the round-trip delay time by 590 times and energy consumption by 50.5 times; and iii) improve the throughput under WiFi and BLE coexistence scenarios.

High-Granularity Modulation for OFDM Backscatter

“…DISCUSSION AND CONCLUSION Although our system was tested using USRPs, we believe that our Lite TScatter has the potential to be deployed on commodity WiFi devices with minimal modification, as it retains symbol-level modulation and XOR-based decoding while serving as a natural extension of existing OFDM backscatter systems. Based on the description of prior works and WiFi specifications [6], [7], [8], [18], [33], implementing Full TScatter on commodity devices would require addressing the following engineering challenges: 1) As backscattered WiFi packets are modified, commodity receivers may discard them due to CRC errors. Similar to other WiFi backscatter systems, TScatter could employ a WiFi card in monitor mode to receive packets even with bad checksums.…”

Cross-Technology Communication for the Internet of Things: A Survey

“…The presence and absence of high rate UDP packets represent the CTC symbol "1" and "0", respectively. TwinBee [99] WiFi → ZigBee Yes / Low High LongBee [100] WiFi → ZigBee Yes / Low High SymBee [101] ZigBee → WiFi No 31.25 Kbps Low High Chiron [102] WiFi ↔ ZigBee Yes 223.97 Kbps Low High PIC [103] WiFi ↔ BLE Yes 121.02 Kbps Low High Symphony [104] ZigBee, BLE → LoRa During the transmission of WiFi packets, the ZigBee receiver conducts energy sensing and collects the RSSI sequence. Then it uses the minimum RSSI fraction or average RSSI as an indicator to distinguish the presence or absence of the WiFi UDP packets.…”

“…Part of them are to enhance the robustness of CTC, such as TwinBee [99], LongBee [100] and SymBee [101]. Other works are to achieve parallel communication between the different wireless protocols, such as Chiron [102] and PIC [103]. We introduce these representative works below.…”

“…PIC [103] design a new gateway to achieve the parallel inclusive bi-directional transmission of both WiFi and BLE data simultaneously. The core of the PIC's design is to generate a frame that contains both WiFi and BLE data which can be demodulated by both WiFi and BLE devices, leveraging the unique modulation schemes of WiFi and BLE.…”