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Protocols for a Tactical Full-Duplex Radio in Support of EW/Communications

Description:

TECHNOLOGY AREA(S): Info Systems 

OBJECTIVE: The objective of this topic is to design and develop a joint MAC and routing protocol that supports tactical radios operating in full-duplex (FD) UHF/VHF band, and simultaneous electronic warfare (EW) and communications capability. The development of full-duplex radios is emerging for the unlicensed band and the current research has focused on development of the physical layer to provide point to point links and increase capacity. Taking advantage of the physical layer breakthroughs in full-duplex, which cancels self-interference, will entail the re-design of some of the upper layer protocols, such as scheduling and routing. 

DESCRIPTION: The development of full-duplex radios has a benefit for the Army in that it allows an increase in MANET network capacity and also simultaneous electronic warfare (EW) and communications. However, to get the maximum gain out of the unique characteristics of a full-duplex capability for future MANET wireless communication, it is important to design intelligent full-duplex scheduling and routing protocols. Current tactical radios cannot simultaneously transmit and receive on the same channel since the self- interference generated when transmitting is orders of magnitude stronger than the received signal. In addition, the scheduling and routing protocols are designed for half-duplex radios. Current breakthroughs at the physical layer such as circulators, analog circuitry, digital signal processing (DSP) techniques and the antenna technologies promise to provide 40-80db in self-interference cancellation. Its feasibility has been shown with off-the-shelf components [1, 2, 3]. However current scheduling designs for full duplex have been so far centralized in nature and geared towards hub and spoke network configurations. Some research has been done on cellular networks with the goal of implementing a full-duplex MAC protocol that builds on IEEE 802.11 [4] and in wireless networks where a novel MAC algorithm is developed that exploits self-interference cancellation and increases spatial re-use [5]. As this research indicates, some of the key challenges for full-duplex MAC development are to coordinate multiple simultaneous transmissions that respects the selection of FD transmission modes and nodes, the fairness among nodes, the hidden node problem, and the contention in asynchronous FD mode. Also, this research indicates that the full-duplex transmission in wireless MANET networks needs a direct coupling between the routing layer and the MAC layer in order to alleviate the cross-interference relationship between the links in the network. This cross-interference can make it very difficult to fully exploit the potential of efficient FD transmission. To this end, innovative research is required to develop a cross-layer framework that encapsulates both routing and a distributed MAC with power control that is implementable on FD wireless ad-hoc networks. The routing coupled with the MAC should have the capability that all links in any routing path can be activated simultaneously, effectively forming a cut-through route [8], wherein each node along the route can simultaneously receive a new packet from the upstream node and forward a previously received packet to its downstream node. In addition to this requirement, the approach should allow a collection of nodes from the network to have the capability of engaging in jamming and communications simultaneously. The resulting framework should take the form of a decision engine that allows this collection of nodes to be intelligently selected in order to optimize jamming and communications capability. All of these features should be scalable and show performance gains in throughput, latency, and packet loss. 

PHASE I: Explore and design routing and scheduling algorithms as to their applicability in an FD wireless tactical networks. The MAC protocols TDMA, CSMA, and CDMA should be assessed as to their applicability in satisfying the requirements as described above. Formulate the capabilities of the routing and MAC scheduling in the context of a decision engine that allows simultaneous EW and communication functions on a single radio platform. This decision engine primarily will select the nodes in the wireless network that are to function as jammers. The performance and scalability properties of the chosen approach and the algorithms should be substantiated by means of modeling and quantitative analysis. 

PHASE II: Refine the design of the decision engine and the algorithms and develop specification of the networking protocols which make use of the algorithms from phase I. Provide software implementation of the proposed protocols and algorithms, and devise demonstration of capabilities using a network of wireless mobile nodes under a military relevant scenario. Demonstrate the simultaneous EW and communication functions based on the proposed solution using a combination of wireless mobile nodes and network simulation/emulation tools. 

PHASE III: The proposed research can be used to improve the network capacity and EW capabilities of Army tactical networks, as well as improving situational awareness. The proposed solution can be incorporated in future tactical radios so that the EW coordination issue is resolved more effectively. In addition to military applications, full-duplex could be used extensively in First Responder and Homeland Security communication systems. Commercial cellular service providers are expected to introduce full-duplex capabilities to handheld devices and relay devices in the near future. Envisioned improvements resulting from this research can also be inserted in these commercial applications and thus enable broader use of their capabilities. 

REFERENCES: 

1: J. I. Choi, M. Jain, K. Srinivasan, P. Levis, and S. Katti. Achieving Single Channel, Full Duplex Wireless Communication. In Proceedings of the 16th Annual International Conference on Mobile Computing and Networking, MobiCom’10. ACM, 2010

2:  S. S. Hong, J. Mehlman, and S. Katti. Picasso: flexible rf and spectrum slicing. In Proceedings of the ACM SIGCOMM 2012 conference on Applications, technologies, architectures, and protocols for computer communication, pages 37–48. ACM, 2012.

3:  M. Jain, J. Choi, T. Kim, D. Bharadia, S. Seth, K. Srinivasan, P. Levis, S. Katti, and P. Sinha. Practical, Real-time, Full duplex Wireless. In Proceedings of the 17th Annual International Conference on Mobile Computing and Networking, MobiCom’11, pages 301–312. ACM, 2011.

4:  A. Sahai, G. Patel, and A. Sabharwal. Pushing the Limits of Full-duplex: Design and Real-time Implementation. arXiv: 1107.0607, 2011.

5:  N. Singh, D. Gunawardena, A. Proutiere, B. Radunovic, H. Balan, and P. Key. Efficient and Fair MAC for Wireless Networks with Self-interference Cancellation. In Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), 2011 International Symposium on, pages 94–101. IEEE, 2011.

6:  K. M. Thilina, H. Tabassum, E. Hossain, D. I. Kim. Medium access control design for full duplex wireless systems: challenges and approaches, IEEE Communications Magazine Year: 2015

7:  X. Fang, D. Yang, G. 2673512Xue. Distributed Algorithms for Multipath Routing in Full-Duplex Wireless Networks, 2011 Eighth IEEE International Conference on Mobile Ad-Hoc and Sensor Systems

8:  Y. Yang and N.B. Shroff. Scheduling in Wireless Networks with Full Duplex Cut-through Transmission, Computer Communications (INFOCOM) 2015.

KEYWORDS: Full-Duplex, MAC, Wireless, Ad-hoc, Cross-layer, Tactical Wireless Network 

CONTACT(S): 

Siamak Samoohi 

(443) 395-7766 

siamak.samoohi.civ@mail.mil 

Mitesh Patel 

(443) 395-7630 

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