This paper focuses on power control in relay-enhanced multicell networks with universal frequency reuse for maximizing the overall system throughput, subject to interference and noise impairments, and individual power constraints at both BSs and RSs. With a high signal-to-interference-plus-noise ratio (SINR) approximation, an energy efficiency based power allocation algorithm is proposed to achieve the maximum sum throughput with the least power consumption. Moreover, an iterative quasi-distributed power allocation algorithm is also presented, which is suitable for any SINR regime. Numerical results indicate that the proposed algorithms approach the optimal power allocation and the system performance can be significantly improved in terms of network throughput and energy efficiency.

As a prominent feature of Named Data Networking (NDN), in-network caching plays an important role in improving the performance of content delivery. However, if each NDN router indiscriminately caches every data packet passing by (i.e., Caching Everything Everywhere (CEE)), the result can be unnecessarily frequent cache replacement and cache redundancy in en-route routers and thus in-network caches are not utilized in an efficient way [1], [2]. Moreover, managing these in-network caches in a centralized way may lead to excessive resource consumption since the number of these caches is considerable. This work proposes a distributed and opportunistic on-path caching scheme. To be specific, each en-route router independently picks content items to cache in such a way that popular content is more likely to be cached by routers, especially routers near users, and cache redundancy is reduced. Extensive simulations including trace-driven ones in a PoP-level ISP topology suggest that the proposed scheme improves the average cache hit ratio of users' requests and reduces the average hop count as compared to CEE and the other on-path caching algorithms considered herein.

Round-trip time (RTT) is an important performance metric. Traditional RTT estimation methods usually depend on the cooperation of other networks and particular active or passive measurement platforms, whose global deployments are costly and difficult. Thus a new RTT estimation algorithm, ME algorithm, is introduced. It can estimate the RTT of two hosts communicating through border routers by using TCP CUBIC bulk flow data from those routhers without the use of extra facilities, which makes the RTT estimation in large-scale high-speed networks more effective. In addition, a simpler and more accurate algorithm — AE algorithm — is presented and used when the link has large bandwidth and low packet loss rate. The two proposed algorithms suit sampled flow data because only duration and total packet number of a TCP CUBIC bulk flow are inputs to their calculations. Experimental results show that both algorithms work excellently in real situations. Moreover, they have the potential to be adapted to other TCP versions with slight modification as their basic idea is independent of the TCP congestion control mechanism.