Optimal file splitting for wireless networks with concurrent access

Abstract. The fundamental limits on channel capacity form a barrier to the sustained growth on the use of wireless networks. To cope with this, multi-path communication solutions provide a promising means to improve reliability and boost Quality of Service (QoS) in areas that are covered by a multitude of wireless access networks. Today, little is known about how to effectively exploit this potential. Motivated by this, we consider N parallel communication networks, each of which is modeled as a processor sharing (PS) queue that handles two types of traffic: foreground and background. We consider a foreground traffic stream of files, each of which is split into N fragments according to a fixed splitting rule (α1, . . . , αN ), where P αi = 1 and αi ≥ 0 is the fraction of the file that is directed to network i. Upon completion of transmission of all fragments of a file, it is re-assembled at the receiving end. The background streams use dedicated networks without being split. We study the sojourn time tail behavior of the foreground traffic. For the case of light foreground traffic and regularly varying foreground filesize distributions, we obtain a reduced-load approximation (RLA) for the sojourn times, similar to that of a single PS-queue. An important implication of the RLA is that the tail-optimal splitting rule is simply to choose αi proportional to ci − ρi, where ci is the capacity of network i and ρi is the load offered to network i by the corresponding background stream. This result provides a theoretical foundation for the effectiveness of such a simple splitting rule. Extensive simulations demonstrate that this simple rule indeed performs well, not only with respect to the tail asymptotics, but also with respect to the mean sojourn times. The simulations further support our conjecture that the same splitting rule is also tail-optimal for non-light foreground traffic. Finally, we observe near-insensitivity of the mean sojourn times with respect to the file-size distribution

Increasing Performances of TCP Data Transfers Through Multiple Parallel Connections

Although Transmission Control Protocol (TCP) is a widely deployed and successful protocol, it shows some limitations in present-day environments. In particular, it is unable to exploit multiple (physical or logical) paths between two hosts. This paper presents PATTHEL, a session-layer solution designed for parallelizing stream data transfers. Parallelization is achieved by striping the data flow among multiple TCP channels. This solution does not require invasive changes to the networking stack and can be implemented entirely in user space. Moreover, it is flexible enough to suit several scenarios - e.g. it can be used to split a data transfer among multiple relays within a peer-to-peer overlay networ

Millimeter-wave Wireless LAN and its Extension toward 5G Heterogeneous Networks

Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are considered as a promising solution for gigabit short range wireless communication systems. IEEE standard 802.11ad, also known as WiGig, is standardized for the usage of the 60 GHz unlicensed band for wireless local area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved to support bandwidth-intensive multimedia applications. Exhaustive search along with beamforming (BF) is usually used to overcome 60 GHz channel propagation loss and accomplish data transmissions in such mmw WLANs. Because of its short range transmission with a high susceptibility to path blocking, multiple number of mmw access points (APs) should be used to fully cover a typical target environment for future high capacity multi-Gbps WLANs. Therefore, coordination among mmw APs is highly needed to overcome packet collisions resulting from un-coordinated exhaustive search BF and to increase the total capacity of mmw WLANs. In this paper, we firstly give the current status of mmw WLANs with our developed WiGig AP prototype. Then, we highlight the great need for coordinated transmissions among mmw APs as a key enabler for future high capacity mmw WLANs. Two different types of coordinated mmw WLAN architecture are introduced. One is the distributed antenna type architecture to realize centralized coordination, while the other is an autonomous coordination with the assistance of legacy Wi-Fi signaling. Moreover, two heterogeneous network (HetNet) architectures are also introduced to efficiently extend the coordinated mmw WLANs to be used for future 5th Generation (5G) cellular networks.Comment: 18 pages, 24 figures, accepted, invited paper

Optimal job splitting in parallel processor sharing queues

The main barrier to the sustained growth of wireless communications is the Shannon limit that applies to the channel capacity. A promising means to realize high-capacity enhancements is the use of multi-path communication solutions to improve reliability and network performance in areas that are covered by a multitude of overlapping wireless access networks. Despite the enormous potential for capacity enhancements offered by multi-path communication techniques, little is known about how to effectively exploit this. Motivated by this, we study a model where jobs are split and downloaded over N multiple parallel networks, each of which is modeled as a processor sharing (PS) queue. Each job is fragmented, according to a fixed splitting rule α=

Cloud Cooperated Heterogeneous Cellular Networks for Delayed Offloading using Millimeter Wave Gates

Increasing the capacity of wireless cellular network is one of the major challenges for the coming years. A lot of research works have been done to exploit the ultra-wide band of millimeter wave (mmWave) and integrate it into future cellular networks. In this paper, to efficiently utilize the mmWave band while reducing the total deployment cost, we propose to deploy the mmWave access in the form of ultra-high capacity mmWave gates distributed in the coverage area of the macro basestation (Macro BS). Delayed offloading is also proposed to proficiently exploit the gates and relax the demand of deploying a large number of them. Furthermore, a mobility-aware weighted proportional fair (WPF) user scheduling is proposed to maximize the intra-gate offloading efficiency while maintaining the long-term offloading fairness among the users inside the gate. To efficiently link the mmWave gates with the Macro BS in a unified cellular network structure, a cloud cooperated heterogeneous cellular network (CC-HetNet) is proposed. In which, the gates and the Macro BS are linked to the centralized radio access network (C-RAN) via high-speed backhaul links. Using the concept of control/user (C/U) plane splitting, signaling information is sent to the UEs through the wide coverage Macro BS, and most of users’ delayed traffic is offloaded through the ultra-high capacity mmWave gates. An enhanced access network discovery and selection function (eANDSF) based on a network wide proportional fair criterion is proposed to discover and select an optimal mmWave gate to associate a user with delayed traffic. It is interesting to find out that a mmWave gate consisting of only 4 mmWave access points (APs) can offload up to 70 GB of delayed traffic within 25 sec, which reduces the energy consumption of a user equipment (UE) by 99.6 % compared to the case of only using Macro BS without gate offloading. Also, more than a double increase in total gates offloaded bytes is obtained using the proposed eANDSF over using the conventional ANDSF proposed by 3GPP due to the optimality in selecting the associating gate.