John Cartmell

Local selected IP Traffic Offload Reducing traffic congestion within the mobile core network

Selected Internet Protocol (IP) Traffic Offload (SIPTO) is a feature defined in the 3GPP standards. In this paper we propose a Converged Gateway (CGW) which enables the SIPTO functionality to be performed locally, before data reaches the edge of the Evolved Packet Core (EPC) network. This feature relieves the EPC from high-bandwidth flows that could otherwise cause significant congestion. This local SIPTO functionality within the CGW identifies the IP Flow type, applies a local user policy rule (optionally provisioned from the mobile core network), and then executes the offloading.

Meeting lawful interception requirements for selected IP traffic offload and local IP access traffic

Cellular network operators are dealing with the increased data requirements of their customers by attempting to offload traffic from the mobile core network. The 3rd Generation Partnership Project (3GPP) standards have defined several strategies that allow for offloading user traffic from the mobile core network. The 3GPP standards also define requirements for the mobile networks to support lawful interception of subscriber traffic. The current methods employed by mobile network operators to perform lawful interception are insufficient to support the traffic offload methods. This paper describes the current lawful interception landscape as well as the methods to perform traffic offload. It then proposes the architecture and methods that allow for traffic offload while satisfying law enforcement needs.

Field trial results for a Wi-Fi based spectrum sharing technology in TVWS

We describe performance results for a Dynamic Spectrum Management (DSM) Platform, including over-the-air data captured outdoors near our Melville, NY facility and in an indoor office environment. The DSM system configuration used to generate the results, and the flexibility of the DSM system that allows it to operate in different bandwidth TV channels are presented. The results include data throughput, received signal strength indicator (RSSI), signal-to-noise plus interference (SNIR) and spectrum coexistence data. We analyze the results, including the advantages and efficiency of channel aggregation, and discuss lessons learned during the measurement campaign that apply to future deployments of spectrum sharing equipment.

Over-the-air performance results of a dynamic spectrum management Wi-Fi system in TVWS

A Dynamic Spectrum Management (DSM) Wi-Fi Prototype Platform is described in this paper. The platform hosts a modified 802.11n waveform that operates in TV White Space (TVWS), receives channel lists from a TVWS database, evaluates channel quality, and selects and aggregates data transmitted across up to four noncontiguous channels. The over-the-air (OTA) performance results collected in the Melville, New York lab are described. The results include data throughput, received signal strength indicator (RSSI), interference sensing and signal-to-noise plus interference (SNIR). The results are analyzed, including the advantages and efficiency of channel aggregation; indicate issues that were uncovered during testing and present possible solutions.

Local IP Flow Mobility to enhance femtocell benefits for open metro deployment

In this paper we describe the benefits and use cases of femtocell based solutions for metro deployments. We then describe a Converged Gateway (CGW) concept which manages a femtocell and WiFi AP. After explaining the architecture of the CGW and the details of how the CGW interacts with the femtocell, WiFi AP and mobile core network, we explore CGW-based IP Flow Mobility. The various processes that define CGW-based IFOM are explained and examples are provided. There are often choppy waters in the approval process for traditional cell towers where the features of a CGW may provide an acceptable path forward. We discuss several court cases to set the framework, and then consider how a CGW may provide some desirable flexibility.

Mobility for heterogeneous SmallNets

In this paper we consider mobility in a network of converged small-cell gateways, each capable of aggregating cellular and unlicensed bandwidth by combining a WiFi Access Point and a cellular base station within a single-box. A network of such gateways must provide mobility services in a decentralized fashion and we demonstrate how this may be accomplished by taking advantage of Proxy Mobile IPv6 the network-based version of the Mobile IP protocol. We also describe how throughput may be increased and Internet Protocol Flows may be maintained when either the cellular or WiFi connections degrade, improving the user experience. Furthermore, we show how the networks of gateways can be used to offload the mobile core network, using the concepts of Selected Internet Protocol Traffic Offload and Distributed Mobility Management.

Use of Bloom Filters to convey identity of surveillance targets

Local data offload performed at a small cell is not commercially deployed as a result of lawful interception issues. Previous work has described a solution to address these issues where a local node performs the same lawful interception functions as is done within the mobile core network for traffic that is offloaded at that local node. However, one issue with this solution is how to transfer the identities of those under surveillance to the local node. Passing the actual identities of targets of surveillance could comprise the required secretive nature of the surveillance. Another issue with the original solution is that by examining the traffic through a small cell, an unauthorized person could determine that a users traffic is not being locally offloaded; thereby perhaps indicating that person is a target of surveillance. In this paper, we propose the use of Bloom Filters to convey the identities of those subscribers who are the target of surveillance. The solution is presented and an analysis is included to demonstrate the benefits of the solution. This paper demonstrates that the use of the Bloom Filter hides the identities of the subscribers who are under surveillance. As well, the paper demonstrates that the false positives that occur with a Bloom Filter are actually a benefit from a perspective of obfuscating who is the actual target of surveillance.

Non-satellite based field communications system for battlefield deployments

Many wireless systems used by military ground personnel are satellite based. This paper explores a hybrid system that benefits from both satellite and terrestrial wireless technologies while overcoming the limitations of each. We present the architecture, describe the merits, and then explain the essence of the system: IP Flow mobility. After introducing this concept, we describe some of the important aspects that specifically relate to mobility and security.