Wireless TCP Research Articles

Leave No Cash on the Table: An Optimal Approach for Controlling Wireless TCP AIMD

The class of additive-increase/multiplicative-decrease (AIMD) algorithms constitutes a key mechanism for congestion control in modern communication networks, such as the current Internet. However, when wireless links are present, the algorithmic behavior of an AIMD algorithm is distorted. Spurious backoffs may be triggered due to packet reordering and non-congestive loss. Prior solutions are developed based on empirical observations without a complete examination of the available design options, thereby overlooking more efficient algorithmic designs (i.e. cash on the table). In this paper, we provide a systematic approach for attaining an optimal enhancement of wireless TCP AIMD. We formulate the design of wireless TCP AIMD as an optimal control problem with the design space of TCP AIMD as the feasible set. With a complete, formal characterization of the design space, we derive a compensation scheme that gives rise to a family of the optimal AIMD algorithms, which can fully filter out the effects due to packet reordering and non-congestive loss. We further identify some properties that help explain the impact of AIMD-based TCP enhancements systematically on the network. We have devised a simple module that realizes the compensation scheme. The module demonstrates a significant performance improvement over existing wireless TCP enhancements through packet level simulation.

On the Fidelity of NS-3 Simulations of Wireless Multipath TCP Connections.

The multipath transmission control protocol (MPTCP) is considered a promising wireless multihoming solution, and the 3rd generation partnership project (3GPP) includes it as a standard feature in the fifth-generation (5G) networks. Currently, ns-3 (Network Simulator-3) is widely used to evaluate the performance of wireless networks and protocols, including the emerging MPTCP protocol. This paper investigates the fidelity of the Linux kernel implementation of MPTCP in the ns-3 direct code execution module. The fidelity of MPTCP simulation is tested by comparing its performance with a real Linux stack implementation of MPTCP using a hardware testbed for two different setups. One setup emulates the existence of a bottleneck link between the sending and receiving networks, whereas the other setup does not have such a bottleneck. The fidelity of ns-3’s simulation is tested for four congestion control algorithms, namely Cubic, linked-increases algorithm (LIA), opportunistic LIA (OLIA) and wVegas for relatively short and long data flows. It is found that the uplink MPTCP throughput performance exhibited by the ns-3 simulator matches the hardware testbed results only if the flows are long-lived and share no common bottleneck link. Likewise, the MPTCP throughput achieved during a downlink scenario using the ns-3 simulator and the hardware testbed are close to each other across all algorithms except wVegas regardless of the flow size if there is no bottleneck link. Moreover, it is observed that the impact of LTE handover on MPTCP throughput is less significant in the simulator than the real hardware testbed, and it is setup-dependent.

A Review on Machine Learning based Loss Discrimination Algorithm for Wireless TCP Congestion Control

A Review on Machine Learning based Loss Discrimination Algorithm for Wireless TCP Congestion Control

Congestion control vs. link failure: TCP behavior in mmWave connected vehicular networks

The millimeter-wave (mmWave) frequency band presents a viable communication platform for the exchange of large amount of data and communications of Connected Vehicular Networks (CVNs). Its ability to support multi-gigabit data rates and high spatial reuse is especially crucial because of the large volume of data produced by physical entity each second. However, its susceptibility the deafness problem, blockages, and beam misalignment is a major impediment, especially in highly mobile environment such as CVNs. Especially, CVNs are related to the life of human being, network reliability is one of the most important issue. To resolve this problem, recent studies on mmWaves have focused more on the PHY/MAC Layers, while fewer studies have examined the transport layer. In this paper, we examine the performance of TCP in mmWave based vehicular networks, focusing particularly on the effects of congestion and link failure. In addition, we highlight the problems of using conventional TCP in an mmWave CVNs and propose an real-time wireless TCP (RTW-TCP) implementation such mmWave environment. Finally, we compare the performance of the proposed RTW-TCP and conventional TCP. The simulation results show that the proposed scheme maximizes the total network resources by distinguishing link failure from network congestion in an mmWave CVNs.

A Novel Wireless TCP for 5G Mobile Network

A Novel Wireless TCP for 5G Mobile Network

Improvement in Wireless TCP Using Modified Loss Differentiation Algorithm

Improvement in Wireless TCP Using Modified Loss Differentiation Algorithm

Adaptive TCP: A Sender Side Mechanism with Dynamic Adjustment of Congestion Control Parameters for Performance Improvement in WLAN

This paper presents a sender side only TCP mechanism to prevent compromise for bandwidth utilization in IEEE 802.11 wireless networks. In absence of mechanism for accurate and immediate loss discrimination, the TCP sender unnecessarily reduces its Loss Window in response to the packet losses due to transmission errors. At the same time, frequent transmission losses and associated link retransmissions cause inaccuracy for available bandwidth estimate. The proposal, Adaptive TCP tackles the above issues using two refinements. First, sender estimates the degree of congestion by exploiting the statistics for estimated Round Trip Time (RTT). With this, it prevents unnecessary shrinkage of Loss Window and bandwidth estimate. Second, by concluding the uninterrupted evolution of its sending rate in recent past, the Adaptive TCP advances bandwidth estimate under favorable network conditions. This in turn, facilitates for quick growth in TCP’s sending rate after loss recovery and consequently alleviates bandwidth utilization. The authors implement the algorithm on top of TCP NewReno, evaluate and compare its performance with the wireless TCP variants deployed in current Internet. Through intensive simulations it is demonstrated that the Adaptive TCP outperforms other well-established TCP variants, and yields more than 100% of the throughput performance and more than 60% of improvement for bandwidth utilization, compared to TCP NewReno. The simulation results also demonstrated compatibility of Adaptive TCP in a shared wireless environment.

The Wireless TCP Disconnection Management

Disconnection is the real one which influences the transmission of data and media in the wireless environment. Due to the influence on the transmission quality, the disconnections are divided into temporary disconnections and longtime disconnections. To solve the disconnections, Wireless TCP Disconnection Management was propounded, which concludes TCP Fast Reconnection Mechanism for the Temporary Disconnection and User-Defined Times of TFRMTD. First, TFRMTD mechanism in the wireless was discussed in detail, which implements the fast reconnection through giving every client a unique ID and catching the results at the server. Second, UDTT is introduced, which discusses how to judge the failing of TFRMTD on the disconnections and then conclude its a longtime disconnection.

Design of wireless TCP fluid model based on cross layers

Design of wireless TCP fluid model based on cross layers

Quality assurance mechanism based on wireless TCP cross-layer service in mobile Ad Hoc network

Quality assurance mechanism based on wireless TCP cross-layer service in mobile Ad Hoc network

Identifying 802.11 Traffic From Passive Measurements Using Iterative Bayesian Inference

In this paper, we propose a classification scheme that differentiates Ethernet and WLAN TCP flows based on measurements collected passively at the edge of a network. This scheme computes two quantities, the fraction of wireless TCP flows and the degree of belief that a TCP flow traverses a WLAN inside the network, using an iterative Bayesian inference algorithm that we developed. We prove that this iterative Bayesian inference algorithm converges to the unique maximum likelihood estimate (MLE) of these two quantities. Furthermore, it has the advantage that it can handle any general K-classification problem given the marginal distributions of these classes. Numerical and experimental evaluations demonstrate that our classification scheme obtains accurate results. We apply this scheme to two sets of traces collected from two campus networks: one set collected from UMass in mid 2005 and the other collected from UConn in late 2010. Our technique infers that 4%-7% and 52%-55% of incoming TCP flows traverse an IEEE 802.11 wireless link in these two networks, respectively.

Improvement of MAC Protocol Based on Mobile Ad Hoc Network

According to mobile Ad hoc networks’ self-organizing, multi-hop and dynamic changed topology, these characteristics made it impossible that the technology of traditional wire networks were directly used in Ad hoc networks. In Ad hoc networks, the mobility of Ad hoc node is one of the main reasons of the packet loss, which led to frequent retransmission timeout and a serious impact on the performance of wireless TCP. Based on IEEE802.11, this paper proposes three improvement strategies of TCP performance based on PMAC, PLM and RLM of MAC layer, integrates their respective advantages, and gives a comprehensive improvement solution as MAC-SS. The simulation results show that MAC-SS on the TCP performance in terms of throughput and packet loss rate is significantly improved with the increasing speed of the node.

Integration Infrastructure of Token-Based Industrial WSN and TCP

As some prevalent wired networks in industrial field are based on TCP, we proposed a novel integration infrastructure of token-based industrial WSN protocol and TCP, so as to make the application of wireless communication technologies more flexible. In the paper, a protocol conversion infrastructure is presented, which is based on data mapping mechanism. The protocol converter includes two modules: Wireless Industrial Control Network(WICN) master module and TCP host module. WICN master module owns an exclusive data buffer called WICN data buffer. TCP host module also has its own data buffer which is named TCP data buffer. A public data area is used for realizing the data mapping between WICN data buffer and TCP data buffer. By the data mapping mechanism, a station in wired network segment could get the data from WICN by accessing TCP data buffer, and WICN slave station could get the data from wired network via WICN data buffer. By the protocol conversion mechanism based on data mapping, flexible data exchange of heterogeneous networks could be realized.

An Improved TCP Connection Protocol over Wireless Mobile Networks with Mobile Nodes Handoff

Problem Statement: This study proposes a TCP layer protocol (Div-TCP) that aims to give a solution for communication over wireless mobile networks that have the occurrence of handoff at anytime. It describes a topology of wireless mobile network and the handoff process as an ordinary process in that type of networks which may cause segments losses. Approach: Wireless mobile networks have many weaknesses related to bit error, network congestion and weak signals that cause segments losses as well as handoff process. For this reason, wireless mobile network TCP cannot distinguish between losses caused by these weaknesses or by the handoff process. So in handoff case, segments losses will trigger congestion control algorithms that reduce the TCP connection's throughput performance. Results: However, in addition to the previous efforts that provide different algorithms and protocols which aim to come up with different solutions and enhancements for the TCP connection in wireless mobile networks when handoff occurs, I am providing in this study Div-TCP protocol that runs the ordinary TCP algorithms with adding more operations that are concerned to handoff. These operations aim to maintain a suitable RTO at each sender to avoid triggering congestions algorithms and also to maintain the sender's throughput by establishing a TCP connection prior to the handoff occurrence. Conclusions/Recommendations: The protocol's discussion shows how end-to-end TCP connection became more efficient since the new Div-TCP connection after handoff will have good and already built TCP connection and the RTO is too much high at all nodes so there is no fear of a that TCP considers congestion.

Optimization of the transmission mechanism for wireless TCP

A novel method which can detect the possible handoffs for mobile nodes is proposed in this article. The method can be deployed on mobile nodes. So when a possible handoff occurs, mobile nodes can detect and take some necessary actions in time. In this study, the method is also used to optimize the transmission mechanism of Q-TCP. Moreover, the simulation results show that Q-TCP can provide better quality of service (QoS) for mobile nodes when they are moving among different agents.

Probe-Aided MulTCP

An aggregate congestion control mechanism, namely Probe-Aided MulTCP (PA-MulTCP), is proposed in this paper. It is based on MulTCP,a proposal for enabling an aggregate to emulate the behavior of multiple concurrent TCP connections. The objective of PA-MulTCP is to ensure the fair sharing of the bottleneck bandwidth between the aggregate and other TCP or TCP-friendly flows while keeping lightweightness and responsiveness. Unlike MulTCP, there are two congestion window loops in PA-MulTCP, namely the probe window loop and the adjusting window loop.The probe window loop constantly probes the congestion situation and the adjusting window loop dynamically adjusts the congestion window size for the arriving and departing flows within the aggregate Our simulations demonstrate that PA-MulTCP is more stable and fairer than MulTCP over a wide range of the weight N in steady conditions as well as in varying congestion conditions. PA-MulTCP is also responsive to flow arrival/departure and thus reduces the latency of short-lived transfers. Furthermore, PA-MulTCP is lightweight, since it enjoys above advantages at the cost of only an extra probe window loop, which has a marginal influence on the implementation complexity. Finally, the design of PA-MulTCP decouples the congestion management from the other functionalities in the aggregate flow management. As a result, PA-MulTCP could be potentially applied to a wider range of scenarios, e.g. wireless TCP proxies, edge-to-edge overlays, QoS provisioning and mass data transport. TCP, Fairness, Congestion Control, Aggregate Flow Management

EJTCP: Enhanced Jitter-based TCP for Wireless Broadband Networks *

TCP is one of the most important and widely adopted transport protocols at present. With the advent of advanced wireless broadband technologies, TCP must be properly tuned and enhanced from traditional networks made up of purely wired links to wiredcum-wireless networks. As a result of high bit error rate (BER) in wireless links, TCP halves down its congestion window unnecessarily caused by random packet loss event continuously, and the performance is significantly degraded in wireless networks. The problem about differentiating congestion loss and random loss has been investigated recently by a number of wireless TCP solutions, such as JTCP (jitter-based TCP). While the existing solutions are accomplishing fundamental efforts to distinguish packet losses, some unavoidable events may occur to make TCP timeout frequently. Hence, we amend JTCP scheme to design a smooth transmission scheme to increase the correctness of loss distinction and avoid burst transmission. Besides, a novel channel aware scheme is designed to deal with dynamic modulation changing in 802.16 Wireless MAN. The experimental results show that our scheme, enhanced JTCP (EJTCP), unrolls significantly better performance than other algorithms over wired-cum-wireless network.

Optimal TCP segment size for mobile server access over wireless links of cellular networks

AbstractInternet access from mobile phones over cellular networks suffers from severe bandwidth limitations and high bit error rates over wireless access links. Tailoring TCP connections to best fit the characteristics of this bottleneck link is thus very important for overall performance improvement. In this work, we propose a simple algorithm in deciding the optimal TCP segment size to maximize the utilization of the bottleneck wireless TCP connection for mobile contents server access, taking the dynamic TCP window variation into account. The proposed algorithm can be used when the product of the access rate of the wireless link and the propagation time to mobile contents servers is not large. With some numerical examples, it is shown that the optimal TCP segment size becomes a constant value when the TCP window size (WS) exceeds a threshold. One can set the maximum segment size (MSS) of a wireless TCP connection to this optimal segment size for mobile contents server access for maximum efficiency on the expensive wireless link. Copyright © 2007 John Wiley & Sons, Ltd.

TCP with gateway adaptive pacing for multihop wireless networks with Internet connectivity

This paper introduces an effective congestion control pacing scheme for TCP over multihop wireless networks with Internet connectivity. The pacing scheme is implemented at the wireless TCP sender as well as at the Internet gateway, and reacts according to the direction of TCP flows running across the wireless network and the Internet. Moreover, we analyze the causes for the unfairness of oncoming TCP flows and propose a scheme to throttle aggressive wired-to-wireless TCP flows at the Internet gateway to achieve nearly optimal fairness. The proposed scheme, which we denote as TCP with Gateway Adaptive Pacing (TCP-GAP), does not impose any control traffic overhead for achieving fairness among active TCP flows and can be incrementally deployed since it does not require any modifications of TCP in the wired part of the network. In an extensive set of experiments using ns-2 we show that TCP-GAP is highly responsive to varying traffic conditions, provides nearly optimal fairness in all scenarios and achieves up to 42% more goodput for FTP-like traffic as well as up to 70% more goodput for HTTP-like traffic than TCP NewReno. We also investigate the sensitivity of the considered TCP variants to different bandwidths of the wired and wireless links with respect to both aggregate goodput and fairness.

Improving Wireless TCP Throughput by a Novel TCM-Based Hybrid ARQ

A novel hybrid ARQ (HARQ) scheme using a concatenated two-state trellis-coded modulation (CT-TCM) code is proposed for improving wireless TCP throughput. A distinguished feature of the proposed scheme is that the heavily punctured TCM codes are used for retransmissions of the corrupted data block, which are combined at the receiver with the previously received sequences of the same data block for decoding. By this method, significantly improved coding gain and efficient spectrum utilization can be achieved with very low complexity. A Markov model is developed to evaluate TCP throughput over the proposed HARQ in wireless link. By both analysis and simulation, we demonstrate that compared with other existing TCM-based ARQ schemes, significant improvement of TCP throughput over wireless links is achieved by the proposed CT-TCM HARQ while smaller buffer size is required at the access point.