Portal

Abstract

Opportunistic forwarding seizes early forwarding opportunities in duty-cycled networks to reduce delay and energy consumption. But increasingly serious Cross-Technology Interference (CTI) significantly counteracts the benefits of opportunistic forwarding. Existing solutions try to reserve the channel for low-power networks by implicit avoidance or explicit coordination but ignore the potential of highpower CTI's superior capability. In this paper, we propose a new paradigm for low-power opportunistic forwarding in CTI environments. Instead of keeping high-power CTI devices silent, we directly involve them into the forwarding, as cross-technology forwarders. We design Portal to solve the challenges of realizing cross-technology opportunistic forwarding. To be transparent to the low-power networks, Portal adopts cross-technology rebroadcasting to enable the fast overhearing and forwarding of cross-technology data. To maximize the performance gain of using heterogeneous forwarders while minimizing the influence on legacy high-power traffic, we propose a post-forwarding forwarder selection and a traffic scheduling method. We also propose a feature-based ACK recognition method and a jamming-based ACK replying mechanism to forward the unreliable ACKs from asymmetric regions. Extensive experiments demonstrate that Portal not only avoids the CTI but also breaks through the existing performance limit. CCS CONCEPTS • Networks → Network protocol design; Ad hoc networks; Routing protocols; • Computer systems organization → Sensor networks.

Enabling Cross-Technology Coexistence for ZigBee Devices Through Payload Encoding

“…Gsense [25] makes a WiFi device transmit coordination information to ZigBee devices through a customized preamble, thus to schedule their transmissions. In recent years, some methods utilize the emerging cross-technology communication (CTC) [5], [6], [26]- [28] to achieve interference management by enabling explicit coordination between heterogeneous devices [13], [14], [29]- [32]. For instance, ECC [13] makes a WiFi AP coordinate data transmissions of all the WiFi and ZigBee devices to avoid interference, thus achieves high network throughput; ECT [29] designs the network layer for CTC and lets a server schedule ZigBee transmissions; Chiron [30] designs a customized gateway to enable concurrent transmissions of WiFi and ZigBee data streams in the same frequency band to reduce the transmission delay; BiCord [32] utilizes bidirectional coordination among heterogeneous devices for efficient RF channel allocation.…”