When the Device is the Network with Mesh, P2P and D2D: "Device-to-Device Communications Underlaying Cellular Networks"
Authors: Daquan Feng; Lu Lu ; Yi Yuan-Wu ; Li, G.Y. Gang Feng ; Shaoqian Li
Title: "Device-to-Device Communications Underlying Cellular Networks"
Publication: Communications, IEEE Transactions on - August 2013
Smartphones, mobile apps, mesh networking, WiFi, and Bluetooth technologies are giving users new and enhanced ways to communicate without using Internet or Cellular Networks, or supplementing them with additional capabilities.
An example of these innovative enhanced ways to use communications technologies comes from recent events in Hong Kong. The WSJ reports how the pro-democracy movement is relaying on mobile messaging apps, to communicate without using cellular or internet service. Using a unique combination of communication technologies available in smartphone platforms, in radio technologies, and in networking, a mobile messaging app, FireChat, creates peer-to-peer (P2P) connections between devices to transfer messages (text, pictures, etc.) to nearby phones via mainly Bluetooth, until they reached the desired user(s). Messages can only move to other phones which have the application installed and are within range (a few hundred feet.) The version 2.0 of the app supports multi-hop WiFi mesh networking and channel bonding. Apple’s iOS platform supports this application via the Multipeer Connectivity Framework.
These technologies might someday be used to tie together thousands of devices and make possible to be online without the need of a traditional network, or a network operator. They could also facilitate emergency or disaster communications in the absence of Cellular towers and/or network connectivity. They could also – like in our featured article cooperate and integrate with the Cellular Network.
The article "Device-to-Device Communications Underlying Cellular Networks" is one of IEEE Transactions on Communications (TCOM) articles that Robert Shober, Editor in Chief of this publication, highlights in his list of the Top-10 TCOM downloaded articles. The article deals with the integration and coexistence of traditional cellular and new D2D based communications. It argues that in cellular networks, proximity users may communicate directly without going through the base station, which is called Device-to-device (D2D) communications and it can improve spectral efficiency. However, D2D communications may generate interference to the existing cellular networks if not designed properly. The article looks at a resource allocation problem to maximize the overall network throughput while guaranteeing the quality-of-service (QoS) requirements for both D2D users and regular cellular users (CUs). A three-step scheme is proposed. It first performs admission control and then allocates powers for each admissible D2D pair and its potential CU partners. Next, a maximum weight bipartite matching based scheme is developed to select a suitable CU partner for each admissible D2D pair to maximize the overall network throughput. Numerical results show that the proposed scheme can significantly improve the performance of the hybrid system in terms of D2D access rate and the overall network throughput. It also shows that the performance of D2D communications depends on D2D user locations, cell radius, the numbers of active CUs and D2D pairs, and the maximum power constraint for the D2D pairs.