Cross Layer Design For Qos

Published Date: 02 Nov 2017

Vehicular ad hoc networks (VANETs) has the potential in improving road safety and in providing travelers comfort. Vehicular ad hoc networks (VANETs) are special cases of mobile ad hoc networks (MANets) in which mobile vehicles are free to move randomly. VANETs is like MANets in case without pre-existing fixed infrastructure, end-to-end multi-hop communications are based on packet relay through mobile vehicles, which are acting as routers. The movement of the vehicles leads topology of the network in VANETs changes more often also causes traffic load condition to change dynamically. The effects of vehicle mobility on QoS management such as traffic flow control, routing path selection, mobile channel assigning, control overhead estimation, fairness have been concerned by many researchers. Moreover, with fast developing of hardware infrastructure, not only QoS of emergency or safety-related applications but also high-bandwidth applications (such as on board Internet access, point-of-interest notification, e-map download) have been considered.

In this project, we will focus on QoS of VANETs in two terms:

(1) Research unfairness problem in MAC layer of VANETs, and then we will propose a solution to improvement MAC layer mechanism in VANETs.

(2) Cross-layer design for QoS of various applications in VANETs.

Overview of Research situation and the necessity of the project

2.1. Literature review

Review and discuss related research works by Vietnamese and foreign scientists. Identify academic/ research institutions involved in associated research. Compare the contemporaneity of researches in Vietnam with developed countries’.

State related past research works of the Principal Investigator. Identify unsolved problems build on past works.

All over the world, traffic congestion is becoming more and more a key challenge for a sustainable development of urban transport network. White Paper—European Transport Policy for 2010 said that "The costs attributable to congestion will also increase by 142% to reach 80 billion a year, which is approximately 1% of Community GDP." In Vietnamese, traffic congestions, accidents also the big problem. We chose 2 years 2012 and 2013 as Transport Safety Years.

As Wikipedia, the total fatalities number comes from the WHO report and is often an estimated number of road traffic deaths based on method used in the report.

Country

Road fatalities

per 100,000

inhabitants

per year

Road

fatalities

per

100,000

motor

vehicles

Total fatalities latest year

Last year source

 Argentina

13.7

43.8

7,485

2012

 Australia

5.71

8

1,291

2011

 Cambodia

12.1

 China

5.1

36

68,000

2009 

 France

5.5

9.57

3,645

2012

 Germany

4.5

7.2

3,657

2010 official figures 

 India

11.1

315.0

133,938

(2010) 

 Indonesia

16.2

210.4

 Japan

3.85

6.8

4,914

2009 official figures

 Laos

18.3

871.4

 Malaysia

24.1

36.5

6,745

2009 end

 Republic of Korea

11.3

26

Official 2010 figure

 Russia

19.5

55.4

27,991

2012 official figures

 United Kingdom

3.59

7

2,222

2009 Dft results (per capita)

 United States of America

12.3

15

33,808

 Vietnam

16.1

55.9

As the table, Vietnamese ratios of Road fatalities per 100,000 inhabitants per year and Road fatalities per 100,000 motor vehicles are very high compare with other countries.

Information and Communication Technologies (ICT) applied to the mobility and transportation sectors, in what is usually referred to as Intelligent Transportation Systems (ITS), has been identified as a promising technology to overcome current limitations and problems of modern mobility systems. An important further innovation step beyond current ITS solutions is the development and future deployment of ICT cooperative systems. Through the use of wireless vehicular communications, cooperative mobility systems aim at assisting road users and infrastructure elements in the gathering of dynamic, ubiquitous and real-time traffic information that will be use to reduce congestions, optimize travel journey’s and minimize emissions.

Research status in the world: Many studies have been done in traffic safety with which many solutions can be envisaged: construction of new roads, promoting public transportation or developing railway transportation, better use of existing infrastructures, and "intelligent" vehicles. Thus, given a fixed urban network for which many types of traffic has to be achieved (public transportation, cars, bicycle, etc.), it is reasonable to think that no real improvements cannot be obtained without better control of this traffic. Since controlling traffic is implemented in practice by traffic control system (red and green light, bus lights, speed indication, etc.), better traffic control systems taking into account the variety of traffic has to be developed.

Another social issue of this project, linked with sensor network technology, is to increase traffic safety. The analysis of the statistics on the road accidents indicates a number of deaths of 3,645 in 2012 in France (that is on average 10 a day). In 2007, the global cost of the road insecurity represented 11,67 billion €. As the preventive safety applications can prevent from the accidents and limit their consequences, the introduction of the new technologies is of a high priority. A significant reduction of injuries and deaths can be only realized by a wide-spread deployment of affordable, active and passive safety technologies embedded in vehicles. The vehicular sensor network technology may be useful to improve the safety and the comfort of the road used, and to reduce the cost-in-use and infrastructure.

Cooperative systems are part of the European Commission’s Intelligent Car Initiative, which is one of the initiatives aimed at raising the visibility of the vital contribution of ICT to the quality of life. An ITS Directive have been recently issued by the European Parliament and of the Council of 7 July 2010 on the framework for the deployment of Intelligent Transport Systems in the field of road transport and for interfaces with other modes of transport (Directive 2010/40/EU). Several projects (CVIS, PRE-DRIVE, DRIVE-C2X, GeoNet, FOTsis, FUI SCOREF, etc.) have developed prototypes and proof-of-concepts to assess the feasibility of wireless vehicular communication technologies. They concentrate especially on some safety and comfort services. However, to keep progressing on the development and implementation of co-operative ITS technologies, further research is needed to evolve from simple applications and small-scale evaluations towards more complex and large-scale systems. This is accentuated for WVSNs especially from the wireless communications point of view where a lot of challenging issues are still remaining.

Research status in Vietnam: Recently, we much focused on applications support for vehicles. Some companies in Vietnam have successfully implement services for safety transport system. E.g Mat Than company provides vehicle monitoring system by capture and recognizing car ID numbers on road. Dr. Nguyen Van Duc in the project "Mobile adhoc networks for traffic management and ambulance service" from Hanoi University of Science and Technology introduced some topologies for surveillance and monitor traffic. Dr. Thai Quang Vinh in the project "Research and development multimedia services and monitoring environment parameters based on WiMAX in Taynguyen" from Institute of Information Technology has the plan to provide Camera IP service for safety transport over WiMAX network. And also, there are some fundamental researches for improvement mechanism of VANET. This field attracts researchers from different fields to develop VANET applications, protocols and simulation tools.

2.2. The necessity of the project

Clearly define the problem or hypothesis to be addressed

Originality, relevance and scientific significance of the question under investigation.

Problem 1: Research unfairness problem in MAC layer of VANETs, and then we will propose a solution to improvement MAC layer mechanism in VANETs

In VANETs, IEEE 802.11p [ISD10] is an approved amendment to the IEEE 802.11 [ISD07] standard to add wireless access in vehicular environments (WAVE). It defines enhancements to 802.11 (the basis of products marketed as Wi-Fi) required to support Intelligent Transportation Systems (ITS) applications. The channel access mechanism in IEEE 802.11 [ISD07] is control by Distributed Coordination Function (DCF) [GBI00]. DCF uses Binary Exponential Back-off (BEB) mechanism [KXU02] to choose randomly a back-off value from one to Contention Window (CW) size. So, it seems that all the contending stations will have the same opportunity of access to the shared channel. However, in multi-hop topologies, BEB mechanism often suffers from the unfairness problem and low throughput uses Binary Exponential Back-off (BEB) mechanism [SXU01, GBE04, TRA06].

The unfairness problem of IEEE 802.11 deeply investigated in the past several years. To improve the network performance, some studies tried to distinguish and solve the problems at each layer independently as layered design method, and some studies tried to co-operate some layers to convey important information as cross-layer design method. In layered design method, some studies focused on the malfunctions of IEEE802.11 MAC layer[CCH04, ZLI05]. Li et al. [ZLI05] investigated Extended Inter-Frame Spacing (EIFS) problem, i.e., the fixed EIFS value leads to unfair bandwidth allocation for each station. They proposed flexible EIFS values based on a measurement of the length of Sensing Range (SR) frame. The paper [CCH04] investigated the three-pair problem. The analysis of the three-pair problem in [CCH04] is based on Markov chain and gives some accurate results.

Some other studies considered to modify the BEB mechanism to improve performance of IEEE802.11. The CW size in the BEB mechanism is doubled when a station experiences a packet collision and the CW size is reset to CWmin when a station transmits a packet successfully. To prevent a large oscillation of CW size, some studies tried to adjust the BEB mechanism as Exponential Increase Exponential Decrease (EIED) [NOS03] and Linear/Multiplicative Increase and Linear Decrease (LMILD) [JDE04].

Some studies focused on link layer problems in multi-hop ad hoc networks. Jangeun et al. [JJA03] and Shagdar et al. [OSH06] pointed out the weak point of FIFO scheduling in multi-hop networks. They proposed various queuing schemes based on Round Robin (RR) scheduling to achieve some level of per-flow fairness. The paper [PTG09] proved that the RR scheduling cannot help per-flow fairness due to unfairness at MAC layer. The Probabilistic Control on Round robin Queue (PCRQ) scheduling [PTG09] is proposed by controlling the input/output/turn of RR queues. PCRQ scheduling improves fair bandwidth allocation at MAC layer and achieves good per-flow fairness. Sofra et al. proposed a cross-layer design that uses a metric known as Link Residual Time (LRT) [NSO09] that is computed based on the received power that is observed at the physical layer. The value of LRT can be used in higher layers to make better decisions for hand-off, scheduling, and routing packets. To avoid such an extensive analysis, some researches proposed a bit rate adaptation method [MVU09, PTG10].

Unlike those studies, our solution tries to evaluate fair bandwidth allocation by examining the number flows which are being transmitted in the carrier sensing range of the station, then CW size is adjusted to achieve fair bandwidth allocation even in case of asymmetric topologies. Moreover, we determine a good CW size for each flow to achieve per-flow fairness.

Problem 1’s reference:

[GBI00] G. Bianchi, "Performance analysis of the ieee 802.11 distributed coordination function," IEEE Journal on Selected Areas in ommunications, vol. 18, no. 3, pp. 535–547, 2000.

[SXU01] S. Xu and T. Saadawi, "Does the IEEE 802.11 mac protocol work well in multihop wireless ad hoc networks?" Communications Magazine, IEEE, vol. 39, no. 6, pp. 130–137, 2001.

[NOS03] N. oak Song, B. jae Kwak, J. Song, and L. E. Miller, "Enhancement of IEEE 802.11 distributed coordination function with exponential increase exponential decrease backoff algorithm," IEEE Vehicular Technology Conference, vol. 4, pp. 2775–2778, 2003.

[JJA03] J. Jangeun and M. Sichitiu, "Fairness and qos in multihop wireless networks," IEEE Vehicular Technology Conference, vol. 5, pp. 2936-2940, 2003.

[CCH04] C. Chaudet, I. G. Lassous, E. Thierry, and B. Gaujal, "Study of the impact of asymmetry and carrier sense mechanism in IEEE 802.11 multihops networks through a basic case," in PE-WASUN ’04: Proceedings of the 1st ACM international workshop on Performance evaluation of wireless ad hoc, sensor, and ubiquitous networks. New York, NY, USA: ACM Press, 2004, pp. 1–7.

[JDE04] J. Deng, P. K. Varshney, and Z. Haas, "A new backoff algorithm for the IEEE 802.11 distributed coordination function," in In Communication Networks and Distributed Systems Modeling and Simulation (CNDS’04, 2004, pp. 215–225.

[GBE04] G. Berger-Sabbatel, et. al., "Fairness and its impact on delay in 802.11 networks," in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM’04), vol. 5, Dallas, USA, 2004, pp. 2967–2973.

[ZLI05] Z. Li, S. Nandi, and A. K. Gupta, "ECS: An enhanced carrier sensing mechanism for wireless ad-hoc networks," Computer Communication, vol. 28, no. 17, pp. 1970–1984, 2005.

[OSH06] O. Shagdar, K. Nakagawa, and B. Zhang, "Achieving per-flow fairness in wireless ad hoc networks," Elec. Comm. in Japan, Part 1, vol. 89, no. 8, pp. 37–49, 2006.

[TRA06] T. Razafindralambo and F. Valois, "Performance evaluation of backoff algorithms in 802.11 ad-hoc networks," in PE-WASUN ’06: Proceedings of the 3rd ACM international workshop on Performance evaluation of wireless ad hoc, sensor and ubiquitous networks. New York, NY, USA: ACM Press, 2006, pp. 82–89.

[ISD07] I. S. Department, IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, June 2007, Std. 802.11-2007.

[JCA08] J. Camp, E. Knightly, Modulation rate adaptation in urban and vehicular environments: cross-layer implementation and experimental evaluation, in: J. Sangeetha (Ed.), Proceedings of the 14th ACM International Conference on Mobile Computing and Networking, ACM, 2008, pp. 315–326.

[36] L. Zhou, B. Zheng, B. Geller, A. Wei, S. Xu, Y. Li, Cross-layer rate control, medium access control and routing design in cooperative VANET, Computer Communications 31 (12) (2008) 2870–2882.

[NSO09] N. Sofra, A. Gkelias, K. Leung, Link residual-time estimation for VANET cross-layer design, 2009, pp. 1–5.

[MVU09] M. Vutukuru, H. Balakrishnan, K. Jamieson, Cross-layer wireless bit rate adaptation, ACM SIGCOMM Computer Communication Review 39 (4) (2009) 3–14.

[ISD10] I. S. Department, IEEE 802.11p/D10.0, IEEE Standard Activities Department, January 2010.

[PTG10] PT. Giang, K. Nakagawa, "Cross-Layer Scheme to Control Contention Window for Per-Flow in Asymmetric Multi-Hop Networks," IEICE Transactions 93-B(9): 2326-2335, 2010.

Problem 2: Cross-layer design for QoS of various applications in VANETs

At the present time cars and other private vehicles are used daily by many peoples. The biggest problem regarding the increased use of private transport is the increasing number of fatalities that occur due to accidents on the roads; the expense and related dangers have been recognized as a serious problem being confronted by modern society. VANET provides a wireless communication between moving vehicles. By VANET communications, vehicles could share different kinds of information, for example, safety information for the purpose of accident prevention, post-accident investigation or traffic jams. Moreover, with fast developing of hardware infrastructure, not only QoS of emergency or safety-related applications but also high-bandwidth applications (such as on board Internet access, point-of-interest notification, e-map download) have been considered.

2.3.Probability of success

Analyze the probability of success of the project (solution found or improvement of problems/ questions under investigation).

Objectives

Research scope and content

Approach

Describe research methodology and techniques appropriate for each issue of the project.

Timetable

Main activities

(milestones)

Product

Time

(start-end date)

Person/Org. in charge

Expected results

7.1. Expected scientific outcomes

For example: new theories, methods, materials; scientific significance and potential application

7.2. Tentative publications and knowledge dissemination

Publications

Number of publications

Notes

1

ISI-covered journals

2

Other international journals

3

Scientific conferences

4

National scientific journals

5

Monographs

6

Others

7.3. Expected training results

vensure the quality of multimedia services over wireless ad hoc networks

IEEE 802.11p/WAVE (Wireless Access for Vehicular Environment) is the emerging standardto enable wireless access in the vehicular environment. Most of the research contributions

in this area has focused on safety-related applications, while comfort and information/

entertainment applications (such as on board Internet access, point-of-interest notification,

e-map download) have been considered only recently. Notwithstanding, the user interest

in this kind of applications is expected to become a big market driver in a near future. In

this paper, an extension to IEEE 802.11p is proposed that is compliant with the multichannel

operation of the WAVE architecture and targets at the support of non-safety applications,

while preserving the delivery of safety services. The proposed W-HCF

(WAVE-based Hybrid Coordination Function) protocol leverages controlled access capabilities

on top of the basic contention-based access of the IEEE 802.11p; it exploits vehicles’

position information and coordination among WAVE providers in order to improve performances

of delay-constrained and loss-sensitive non-safety applications.

Such characteristics lead to fairness problem in VANETs, considered in this paper. In fact, vehicles with different speeds have their different limited time to communicate with an access point (AP). This attribute adversely affects the chance of a fast moving vehicle in communicating with the access point. We propose a modified 802.11 DCF channel access scheme as a solution to the problem. The proposed scheme adjusts the probability of transmission at a time slot for each node according to its speed. To this end, we change the probability of transmission through changing the minimum contention window size. In this respect, we obtain some relations between speed and window size through analytical approximations. Simulation results indicate the validity of our approximations and the efficiency of the proposed MAC scheme in solving the fairness problem.

In a vehicular ad hoc network (VANET) without pre-existing fixed infrastructure, end-to-end multi-hop communications are based on packet relay through mobile vehicles, which are acting as routers. Since mobile vehicles are free to move randomly, vehicle mobility is one of the most important issues in protocol design. The effects of vehicle mobility on traffic flow control, routing path selection, mobile channel assigning, control overhead estimation and QoS management have been concerned by many researchers (McDonald and Znati, 1999, Santi and Blough, 2003, Stojmenovic, 2002, Chiang, 1998, Johansson et al., 1999, Bettstetter, 2001, Haas, 1997, Hong et al., 1999, Wang and Baochun, 2002, Garcia and Madrga, 1999, Das et al., 2001, Shen and Du, 2010, Kim et al., 2009, Aschenbrucka et al., 2011, Ahmed et al., 2010 and Zaidi and Mark, 2011), in which a common approach for performance analysis in such networks is the synthetic mobility model on geographical basis by either simulations or realistic vehicular trace data obtained by street measurements (Fan Li and Wang, 2007).

Vehicular ad hoc networks (VANETs) are classified as an application of mobile ad hoc network (MANET) that has the potential in improving road safety and in providing travellers comfort. Recently VANETs have emerged to turn the attention of researchers in the field of wireless and mobile communications, they differ from MANET by their architecture, challenges, characteristics and applications. In this paper we present aspects related to this field to help researchers and developers to understand and distinguish the main features surrounding VANET in one solid document, without the need to go through other relevant papers and articles starting from VANET architecture and ending up with the most appropriate simulation tools to simulate VANET protocols and applications.

However, most of these models are limited to a specific road traffic conditions such as street conditions, urban conditions, traffic conditions and vehicle density.

The data (network flows and number of vehicles) collected in the previous task are the input of this task. These information are needed for the optimization model used to find optimal traffic light timing and dynamic clustering developed in task 2.1. The new movement traces (using the traffic light optimization) will be available for all WVSNs research community as input of their simulators (NS [37], Qualnet [38]) in on order to evaluate their vehicular networks protocols/solutions. It is to know that existing mobility models that are used in simulators did not consider stops of vehicles at stops and traffic light. Hence, our contribution will be well received in the community of protocols engineering in WVSN.

IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to facilitate wireless access in vehicular environments (WAVE). In this article, we present an analytical model to evaluate the impact of vehicle mobility on the saturation throughput of IEEE 802.11p-based vehicle-to-infrastructure (V2I) networks. The throughput model is then used to investigate an unfairness problem that exists in such networks among vehicles with different mobility characteristics. Assuming a saturated network, if all the vehicles in the network use the same MAC parameters, IEEE 802.11p MAC protocol provides equal transmission opportunity for all of them, provided they have equal residence time in the coverage area of a road side unit (RSU). When vehicles have different mobility characteristics (e.g., extremely high and low speeds), they do not have similar chances of channel access. A vehicle moving with higher velocity has less chance to communicate with its RSU, as compared to a slow moving vehicle, due to its short residence time in the coverage area of RSU. Accordingly, the data transfer of a higher velocity vehicle gets degraded significantly, as compared to that of the vehicle with lower velocity, resulting in unfairness among them. In this article, our aim is to address this unfairness problem that exists among vehicles of different velocities in V2I networks. Analytical expressions are derived for optimal minimum CW (CW min) required to ensure fairness, in the sense of equal chance of communicating with RSU, among competing vehicles of different mean velocities in the network. Analytical results are validated using extensive simulations.