Connecting Mobile Phones via Carrier-Grade Meshed Wireless Back-Haul Networks

Meshed wireless back-haul networks are seen as an affordable technology to bring Internet connectivity into rural and previously unconnected regions. To date, the main focus is to provide access to classical services such as the WWW or email. Access to such services requires the users to use a personal computer or a recent smart phone. Especially in developing regions, the prevailing end user device is a mobile phone. In order to connect mobile phones to an IP-based back-haul network, the network access points must provide a mobile phone air interface which is usually based on GSM or UMTS. In order to avoid dependence on a costly 3GPP infrastructure, we propose to deploy GSM or 3GPP nano cells in order to terminate the mobile phone protocols immediately at the mesh access points. Hence, the voice or data traffic can be carried over IP-based networks using open protocols such as SIP and RTP. In this paper we present a meshed wireless back-haul network with access points that have been equipped with GSM nano-cells. The voice traffic generated by the mobile phones is carried across the mesh in parallel to typical web or video traffic. In this paper we evaluate the QoS handling received by the voice calls across our multi-hop wireless testbed and show that our architecture can provide the resource isolation required to offer uninterrupted VoIP services in parallel to typical Internet traffic.