Paridhi Verma’s scientific contributions

Chapter 6 combines techniques on bandwidth management described in Chapter 3 and techniques from cost reduction in Chapter 4 and applies them to the specific case of radio access backhaul networks and cellular core networks. The backhaul is part of the network that connects equipment at cell towers to equipment to the core network. The backhaul may be designed using copper cables, optical fibers, or microwave. The cellular core network is the part of the network that consists of the wired part of the network connecting the backhaul to the IP network owned by the mobile network operator. This IP network in turn connects to and is part of the Internet. The bandwidth on backhaul and core networks is limited mostly by cost and business issues associated with upgrading the network capacity. Approaches like compression and traffic offload can be used to deal with the congestion of backhaul and core networks. Caching in the backhaul or core can be implemented but has to deal with the complexities of extracting packets bound to the Internet from the encapsulations of cellular protocols. Consolidation of functions works well in the core network and has led to a strong push for network function virtualization in the cellular core network.

There are several general techniques for managing bandwidth in any type of computer network. Starting with an abstract model of a network with a congested link, this chapter looks at a variety of such techniques. The congested link is one that has more traffic required to flow on it than it has the capacity to carry. An expensive but simple approach is to add more capacity to the network to eliminate the congestion. Object caching is the technique of moving data objects so as to avoid traversing the congested link when accessing them. Compressing objects allows for reduction in the amount of data that needs to travel on the congested link. A variation on compression allows one to cache bytestreams and operate across multiple protocols. When several flows carrying the same content are flowing on the congested link, one can share content across all of these flows. Another technique is to modify some types of content (e.g., video) to a lower granularity resolution so as to reduce the amount of bytes required to transmit it. The use of rate control mechanisms provides for a fairer sharing of limited resources. Finally, dividing users into different categories and giving preference for one set of traffic over another provide for an alternative approach to deal with congested network links.

The design of mobile applications has a significant impact on the amount of mobile data they use. This chapter provides a high-level overview of mobile applications. Mobile applications typically have a component on the handheld device and another component running on a server in the Internet. The communication protocol used between the two components defines the nature of the application. Web-based mobile applications rely exclusively on the Hypertext Transfer Protocol for such communication, while native protocols use their own private protocol written over the mobile operating systems. A hybrid mobile application uses a mix of these two approaches. Developers of mobile applications have to deal with the issues related to standard software engineering practices. Some of the challenges of normal software development are exacerbated in case of mobile applications because of a large number of devices that exist and the rapidity with which the underlying operating systems change.

Chapter 11 looks at the subject of making power-efficient mobile applications and the techniques an application service provider writing mobile applications can deploy to make that application more power efficient. Battery power is a rather limited resource on the mobile phone, and writing applications that put the minimum drain on the battery is highly desirable. Power management is largely under the control of the operating system on the mobile device, and only a few controls are available to the mobile application developer. Nevertheless, there are some useful techniques that can improve the power efficiency of applications. Clustering power-expensive operations like network communication can improve the power consumption profile of an application. Similar clustering of computation operations allows the operating system to use duty cycling to conserve power, as well as better manage the different power modes the device may be capable of supporting. Some of the best practices that improve power efficiency are minimizing content on devices, maximizing computation on the server side, batching of network requests, and designing for minimum screen brightness and context awareness.

Chapter 5 combines techniques on bandwidth management described in Chapter 3 and techniques from cost reduction in Chapter 4 and applies them to the specific case of radio access networks (RANs). These provide for a set of techniques that allow for reducing the cost of RANs and managing with the demands of growing traffic usage. Both technical and nontechnical approaches that can be applicable to RANs are considered. Nontechnical approaches target adjusting user behavior to extend the life of current networks, while technical approaches provide adjustments to the network to adapt to user demand for additional bandwidth. Technical approaches include upgrading the network infrastructure, augmenting the network bandwidth, traffic offload, rate control, and service differentiation. The use of high-density RANs where spatial redundancy is used to provide additional bandwidth is discussed. Femtocells and the use of Wi-Fi networks provide alternative approaches for traffic offload. Nontechnical approaches include different pricing plans, incentives against bandwidth hogs, and prompting users to switch over to Wi-Fi networks when appropriate.

One of the goals of mobile network operators is to extract more value from the data that is flowing on their networks. One possible way to get this value, or monetize the data, is to offer value-added services that the subscribers of cellular data would be interested in. This chapter explores some services of this nature. The mobile network operators are in a good position to offer some services because they can interpose themselves transparently between the mobile user and the Internet. This allows the operator to offer services like single sign-on or privacy. Single sign-on service allows mobile data subscribers to deal with the problem of exploding set of credentials on the Internet. The privacy service provided by a mobile network operator may be preferable over Internet-based privacy using onion routing to a select set of users. The network operator is also in a better position to provide a seamless experience for some services like customizing content so that it always appears in the preferred language of the subscriber. Providing services based on location of the user, as well as allowing commercial transactions using mobile phones, would open up new opportunities for generating revenues.

The ecosystem of any technology consists of the set of companies, organizations, and people whose business is impacted by the technology or whose business impacts the technology. In the ecosystem, any such entity has its own role to play, usually with a complex set of relationships to other entities in the ecosystem. The mobile data has its own ecosystem in which many different entities play. This chapter provides an overview of this ecosystem, defining different roles and clustering the roles in four groups. The groups are that of standard definers, manufacturers, service providers, and users. The group of standard definers includes the roles of standard organizations and regulatory agencies. The group of manufacturers includes the roles of component providers, either hardware or software; equipment makers for mobile devices; network equipment and servers; as well as developers of mobile applications. The group of service providers includes the role of mobile network operators, Internet service providers, and application service providers that operate on the Internet. The group of users includes consumers and enterprises. Any given company can take more than one role in the ecosystem.