Machine-To-Machine Ad-Hoc Networking with a Redundant 4G LTE Gateway Using BATMAN-Adv

Abstract

The use of mobile devices for Internet usage has been rapidly increasing and thus the demand for wireless networks. There have been plenty of scenarios and cases that mobile consumers and businesses get into areas that do not have a reliable wireless coverage because of terrain, buildings and distance. Most of us had been a situation where we need Internet access desperately and the cellular network coverage is non-existent. For businesses using machine-to-machine communication, deploying an infrastructure network can be costly or be faced with too many regulatory issues. This can slow down deployment of machine-to-machine devices or stop it all together.When it comes to machine-to-machine communication or IoT devices, CatM was created as an LTE standard to address the needs of low data throughput at a cheap price point. The current implemented version of CatM is inefficient considering bandwidth utilization, and cellular carriers are already hard pressed for spectrum. Once a CatM device is activated, even when it is not transmitting, 17% of the available spectrum is reserved. Due to this spectrum reservation, this reduces overall speed for other users and reduces the number of users that can actively use the network. Then the issues everyone experiences, lack of coverage and a clean signal, due to terrain, buildings, regulations, costs and running backhaul, deploying cell sites everywhere is challenging. This is the reason why cellular coverage has dead spots or weak signal strength. With cellular spectrum costing billions of dollars, there is a more cost-effective way to utilize existing bandwidth.To improve upon already established ad-hoc networks, this paper will explores using nodes with an LTE connection and then sharing that LTE connection using BATMAN-Adv to nodes outside the coverage area of the cell site. An application for this could be smart meters located in the basements of houses. A meter might be outside the coverage of a local cell site but could communicate to another meter that is wirelessly visible. This would artificially expand the coverage of the cell site without having to invest in deploying more cell sites for a handful of nodes. The next step the paper will explore is redundancy. This is a critical issue, since missed data can be costly and frustrating. By allowing multiple nodes to share their cellular connection, this creates redundancy for when a node unexpectedly drops or if the local cell site has an outage.BATMAN-Adv is just one of many ad-hoc routing protocols available to be deployed. It was chosen because of its ability to run on Linux kernels out of the box without any modifications required. With the testing that was performed it is evident that BATMAN-Adv can support acceptable latency with solid throughput numbers. Further testing showed that in the event of a node or gateway failure, the protocol can reroute the traffic over another path. Layer 3 connections will drop and must be re-established, this is expected since there is no infrastructure running this network. Lastly pairing this protocol with a cellular modem, makes it possible for this network to be portable. Since only a single node needs to have a cellular uplink and two for redundancy, this means the network can be deployed in places where a traditional network cannot and at a lower cost since expensive routing hardware is not needed. Then with optimized hardware, it is possible to run these devices on batteries or solar, which further enhances the portability of the network.There are limitations to ad-hoc networking, and it should be expected that it will never be as fast or reliable as a traditional infrastructure network. With that in mind, if the correct type of traffic is running over an ad-hoc network, the cost savings and rapid deployment can be taken advantage of. For machine-to-machine networks, when cellular coverage is limited, using an ad-hoc routing protocol can allow the network to be expanded where in many cases it is not possible to add additional cellular coverage or at all.