Ji-Cheol Lee

Towards security architecture for Home (evolved) NodeB: challenges, requirements and solutions

In this paper, we evaluate the options for a viable security architecture for the 3GPP Home (evolved) NodeB (H(e)NB) and present the trade-off between the level of security provided and the associated cost of a H(e)NB device. Low cost of the H(e)NB device is one of the key factors to achieve high market penetration and the major contributor to the cost of the H(e)NB device is the security architecture. It is of interest to analyse the security challenges, security requirements and security mechanisms for (i) H(e)NB authentication, (ii) provisioning of security credentials, (iii) backhaul link protection, (iv) location verification and (v) user access control in the H(e)NB. It is required that the H(e)NB architecture mitigates the threats foreseen by opting a comprehensive security mechanisms amenable to both the operators and the subscribers, while satisfying the acceptable level of security required. Copyright

Performance Analysis of SPDY Protocol in Wired and Mobile Networks

Google proposed the new application-layer protocol named SPDY with the purpose of complementing problems of HTTP/1.1 to improve web speed. In this paper we evaluate the SPDY protocol’s performance in a variety ofmobile environment to examine the characteristics of the SPDY protocol and compare the differences between the existing protocol and SPDY protocol. Also through this performance evaluation, we analyze the problem of SPDY and propose directions for improvement of this protocol.

A performance study of proxy-based TCP rate control design for mobile video streaming services

Reducing startup delay of video streaming is important for attracting more users. In LTE networks, even though available bandwidth has increased, behavior of TCP, which has a slow start phase and estimates available capacity based on packet loss event, increases the startup delay of video streaming. To solve this issue, we design a proxy-based TCP rate control (PTRC) scheme for achieving low startup delay of mobile video streaming by using the explicit radio related information from a base station (BS). We introduce a target queue length (Qtarget) as feedback information to a proxy, which represents a desired value at the BS. Here, the Qtarget is dynamically calculated by referring to average data rate of a radio link and backhaul delay. Then the proxy is informed of this Qtarget by an in-band signaling message from the BS, and controls its sending rate accordingly. Hence, the proposed PTRC scheme can boost up its transmission rates in the initial phase, and keep instant queue length at the BS close to the Qtarget. We verify that the proposed PTRC scheme achieves about 71.2% reduction of startup delay for mobile video streaming in LTE environment, compared to conventional schemes.

Evolution for Mobile Contents Delivery Optimization

As mobile traffic grows, the mobile operators need to handle video delivery in the mobile network to reduce their network cost and to enhance Quality of Experience. In order to address network operators needs, first, we listed up the mechanism for mobile contents delivery optimization solutions. Second, we identified the common two key features, which are caching and media adaptation. Finally, we proposed an architecture evolution of 4G network to support caching and the media adaptation. We discussed the future direction on the key features.