Wireless Pers Commun DOI 10.1007/s11277-015-2760-0
Outage Minimization Using Bivious Relaying Scheme in Vehicular Delay Tolerant Networks Safdar Hussain Bouk1 • Syed Hassan Ahmed1 Babatunji Omoniwa2 • Dongkyun Kim1
•
Springer Science+Business Media New York 2015
Abstract Vehicular delay tolerant networks have proven to be a low-cost solution with an attempt to provide connectivity in the presence of vehicular mobility. In this paper, we propose a bivious relaying scheme to minimize the communication outage experienced by a vehicle within an uncovered area between two distant neighboring Road Side Units (RSUs). Our proposed scheme selects two relays for a target vehicle, one when it leaves the coverage area and the other when it is on the way to enter the next distant RSU. We analyze the effect of our proposed bivious relaying scheme with the existing single relay selection scheme using the interior point algorithm. Monte-Carlo technique is also used with 100,000 iterations to show the behavior of this stochastic process. The analytical results show that the bivious relaying scheme provides a better minimized communication outage time compared to the single relaying scheme. Keywords
VDTN RSU Target vehicle Relaying vehicle Bivious
& Safdar Hussain Bouk
[email protected];
[email protected] & Dongkyun Kim
[email protected] Syed Hassan Ahmed
[email protected] Babatunji Omoniwa
[email protected] 1
School of Computer Science and Engineering, Kyungpook National University, Daegu, Korea
2
Department of Electrical Engineering, COMSATS Institute of Information Technology, Islamabad, Pakistan
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1 Introduction A wide variety of applications for vehicular delay tolerant networks (VDTNs) include provision of business services, web browsing, weather reporting, traffic management, health, road safety and military applications. The VDTN consists of a number of distant stationary Roadside Units (RSUs), which are deployed along the highways and connected to the infrastructure network. To provide longer coverage with the minimum number of RSUs installed and lower maintenance cost, these RSUs are commonly deployed at a substantial distance between adjacent RSUs. In this type of deployment scenario, a vehicle experiences frequent communication outage, especially when traveling on the highway [1, 2]. To overcome this issue, multi-hop relaying techniques have been proposed to extend the RSU’s coverage range [4–8]. However, the multi-hop relaying increases the overall communication delay, high control overhead and low throughput due to the dynamic topology [3]. This paper mainly focuses on the VDTN scenario where information is communicated from RSU to the vehicles, known as downlink communication. It is assumed that all the RSUs are tightly coupled with each other through infrastructure network. There are many existing techniques that resolve mobility management issues, hence, they are not in the scope of this work. In downlink communication scenario the vehicle, where information is destined, is termed as the target vehicle. The target vehicle experiences a communication outage when it exits from the coverage area of the RSU. The communication coverage to the target vehicle can be extended through an intermediate passing-by vehicle between the RSU and target vehicle, called the relay vehicle. The information destined to the target vehicle is stored at the relay vehicle first and then forwarded to the target vehicle. In this manner, the relay vehicle minimizes the communication outage time of the target vehicle. This type of scenario is referred as Infrastructure-to-Relaying-Vehicle (I2RV) [5] and is shown in Fig. 1. To achieve better and longer communication performance between RSU and the target vehicle, it is important to select a proper relay vehicle. In general, the relay selection process in I2RV requires RSU to effectively select a relay vehicle [4–8]. In the initial step of the relay selection process, RSU estimates the location,
RSU 1 Edge Router
Internet Relay Vehicle Target Vehicle
Edge Router RSU 2
Fig. 1 Infrastructure-to-relaying-vehicle (I2RV) architecture
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communication channel condition, distance between RSU and relay candidate(s), speeds of relay candidate(s), etc. This information could then be used by RSU or disseminated by the RSU in the network to effectively select the relaying vehicle. Recently, a relay selection technique to support I2RV, Adaptive Carry-Store Forward (ACSF) scheme, has been proposed [8]. It requires the variation in the speed of the target vehicle in conjunction with the relay vehicle in order to minimize the outage time. The authors proposed that the relay should be selected by the RSU when a target vehicle moves from the left side of the RSU to its right side. We term this type of relay selection as a one-way relay selection. If both target and relay vehicles are in the uncovered area, the target vehicle can receive information only when it enters in a coverage area of the next RSU. The main drawback in RSU dependent schemes is that any relay node which is not in the coverage range of the RSU cannot be selected when the target vehicle moves inside the uncovered area because RSU does not have any information of those vehicles. Therefore, we propose a relay selection scheme where the target vehicle selects relay vehicles on its own or in a distributed manner. Due to this property, two relay vehicles are selected by the target vehicle to maintain downlink communication with RSUs. First, when exiting from the first RSU’s coverage and second, before entering the next RSU’s coverage, called backward and forward relay selection, respectively. These two relays extend coverage to the target vehicle in the uncovered area between two adjacent RSUs and minimize the communication outage of the target vehicle. Both the relays are selected by the target vehicle based on distance, speed and minimum communication outage period between relay and the target vehicle. The contributions of our proposed scheme are as follows: • • • •
Bivious relaying scheme without the support of RSU. Minimize communication outage time. The Target vehicle selects the relay even when it is in the uncovered area of the RSU. Outage time is minimized by the proposed scheme with and without adjusting the speed of the target vehicle based on both the relaying vehicles.
As a distinguishing feature from previous work [8], we consider the prevalence issue of minimizing the communication outage using our bivious relay approach. A novel and improved mathematical model for our proposed scheme is also presented in this paper. For analysis and evaluation of our proposed scheme, the Monte Carlo technique with 100,000 iterations is employed. The remainder of this paper is organized as follows. Recent work in the area of relaying schemes in the I2RV VDTN scenario is discussed in Sect. 2. Section 3 describes our proposed bivious relaying scheme, including discovery, estimation, selection of relaying vehicles and optimization of moving speed of the target vehicle. Analytical results are given in Sect. 4 to demonstrate the efficiency and effectiveness of the proposed scheme. Finally, Sect. 5 concludes the paper.
2 Related Work In this section, we briefly discuss the recent work in the area of relay selections in the I2RV VDTN scenario. The authors in [4] proposed an opportunistic relay protocol for the I2RV network scenario. It uses the multi-user diversity of the fast fading channel to identify the relay candidates in a distributive manner. RSU broadcasts the data packets at an optimal data rate and all the receiving vehicles which could decode those packets successfully become
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relay candidates. The authors proposed an analytical model that selects a relay vehicle from the relay candidates that is closer to the destination vehicle in order to achieve higher data rate. The similar relaying technique was proposed in [5] that analyzes the outage gain and performance of the LTE-A network’s downlink transmission scheme. The authors proposed a relay selection model that uses the link associated Signal to Noise Ratio (SNR) of the channel between source, relay and destination vehicles to select relay vehicle. In [6] the authors proposed an analytical model for multi-hop relay selection scheme that selects an optimal relay among the stationary relays (RSUs are considered as stationary relays) and mobile relays that are moving vehicles. The model considers location of vehicles and link capacity of the path to select the optimum relay. The vehicles in a path with higher capacity links are selected as relay vehicles. The signal space alignment based opportunistic relay selection scheme was proposed in [7]. It estimates the channel using two way communication between RSU and a target vehicle via a relay vehicle and finds one misalignment value based on the transmitted signal, transmit power and received noise at RSU. The relay station with a minimum misalignment value is selected as a relay vehicle. In [8], the authors use a passing-by vehicle to act as store-and-forward relay for the target vehicle in the uncovered area. The authors proposed that the relay is selected by the RSU when a target vehicle moves from the left side of the RSU to the right side. The distance between RSU and the relay vehicle is considered as the relay selection criteria. The RSU selects the relay station and the target vehicle adjusts its speed in conjunction with the relay vehicle in order to minimize the outage time. However, when both target and relay vehicles are in an uncovered area, then the target vehicle can only receive information from the next RSU when it enters in its coverage area. It is observed from the previous work related to the relay selection in the I2RV scenario that RSU performs a main role in the relay selection process. Hence, most of the previous schemes can only select backward relay(s) to extend communication coverage for the target vehicle in the uncovered area. In this paper, we propose a new bivious relay selection scheme for vehicular delay tolerant networks where a target vehicle selects backward and forward relays to minimize the communication outage period. The detailed discussion of the proposed scheme is presented in the next section.
3 Proposed Relaying Scheme for I2RV Scenario In this section, we introduce our proposed bivious relaying scheme for the I2RV with downlink communication scenario in a vehicular delay tolerant network (VDTN). The main objective of the proposed relaying scheme is to minimize the communication outage time of the target vehicle in the uncovered area through selection of the best relay without any help of the RSU. To achieve this objective, the proposed scheme selects relay vehicles to sustain downlink communication to the target vehicle when it exits from and enables it before entering the coverage area of an RSU. The relay selection process involves three steps that include discovery of relay candidates, estimation of relay candidates and the selection of the best relay.
3.1 Discovery of Relay Candidates Consider a VDTN scenario, as shown in Fig. 2, where two RSUs (RSU1 and RSU2) are deployed along the roadside. Each RSU provides coverage within the maximum distance
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Fig. 2 Proposed bivious relay selection scenarios
of 2R, where R is the transmission range of the RSU and the vehicles as well in meters. RSU1 and RSU2 are considered to have a distance of 2R þ U apart, where U is the uncovered distance between the two RSUs. Initially, when a vehicle enters the coverage area of RSU1, it announces its current status, location, velocity, RSU ID that it joined, etc. by sending the A la Carte Message (ACM). The ACM is a flexible message that may contain any data frame or data element defined in the standard [9]. This message is generated by the vehicle to exchange information with the other vehicles or RSU (V2X communication) within its communication range. Let vehicle Vbi (where i ¼ 1; 2) enters the RSU1’s coverage area (refer to Scenario 1 in Fig. 2). After successfully associating or joining RSU1, the vehicle Vbi sends an ACM to announce its acceleration, location, RSU information, status, etc. The vehicles in the transmission range of Vbi , that is, R meters, receive this message and record Vbi ’s information in their neighborhood list. The information includes velocity (vbi ), distance (dbi ) between Vbi and itself, location, RSU ID, status, etc. Similarly, V0 detects forward relay candidate(s) from the vehicles that are moving ahead of V0 enter(s) the coverage area of RSU2 and send(s) ACM (refer to Scenario 2 in Fig. 2). The target vehicle updates its neighborhood table and computes the potential backward and forward relay from the relay candidates that are in the region K, where 0 K R. The estimation of each potential relay from the available relay candidates is discussed below.
3.2 Estimation of Potential Relay Here, we discuss the estimation and selection steps of forward and backward relays. The backward relay selection process considers the distance between V0 and backward relay candidates instead of the distance between a relay candidate and RSU. The backward relay estimation process is adapted from the single relay selection scheme proposed in [8].
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We consider that the selected backward relaying vehicle i has time, t, as expressed in Eq. (1), to store and forward data to V0 . At: t ¼ R=v10 dbi =vbi
ð1Þ
Let v10 and v20 be the velocities of V0 in the coverage area of the RSU1 and in the uncovered area, respectively. The difference in the distance of V0 and Vbi at the instance seen in Fig. 2 is: 1 v t v b t R ð2Þ i 0 which shows that both V0 and Vbi are in the transmission range of each other when V0 leaves the coverage area of RSU1. The distance dbi of the relaying vehicle is considered to be negative, since it is on the left hand side of V0 . R v10 vbi þ v10 dbi R ð3Þ v10 that leads to (4), as in [8]: Rvbi Rvbi v10 2R þ dbi dbi
ð4Þ
The time taken by V0 to move towards the end of RSU1’s coverage area and from the beginning of the uncovered area to the start of coverage area of RSU2, are denoted by t1 and t2 , respectively. Therefore, the total time (t) that V0 is in the coverage of Vbi is given by: t ¼ t1 þ t2
ð5Þ
The time till V0 remains in the coverage area of Vbi is: t¼
R U þ v10 v20
ð6Þ
However, if V0 does not change its speed after entering the uncovered area, then Eq. (6) will be: t¼
RþU v10
The moving speed of V0 in the uncovered area after exiting from the RSU1’s coverage area at a given t must satisfy: R þ v2 ðt2 t1 Þ ðdb þ vb tÞ R ð7Þ i i 0 where: t
R R U ; þ v10 v10 v20
ð8Þ
The condition in (7) must be satisfied only at the end points shown in (8). By substituting the values of t1 ¼ R=v10 and t2 ¼ t in (7), we obtain: R þ v2 t R ð9Þ ðdbi þ vbi tÞ R 0 v10
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The above equation at t ¼ R=v10 has been satisfied in (4). At t ¼ R=v10 þ U=v20 , (9) is solved to: vbi U vbi U v20 1 2R þ U þ dbi vbi R=v0 U þ dbi vbi R=v10
ð10Þ
Equations (4) and (10) guarantee that the V0 can receive communication from RSU1 via Vbi . In case of Scenario 2 in Fig. 2, the proposed scheme discovers and selects the forward relaying vehicle, Vfj , that provides connectivity with RSU2 via Vfj to V0 . The forward relay candidates Vfj that are moving at velocity of vfj with the dfj distance ahead of the V0 , send an ACM once they enter the transmission range of RSU2. Here, dfj R that indicates that Vfj and V0 are in the transmission range of each other. Upon reception of the ACM from Vfj , V0 maintains the entries of the forward relay candidates in its neighborhood table. The Vfj which has just entered the coverage area of RSU2, as shown in Fig. 2, moves at the velocity of vfj ¼ dfj =t. The Vfj should be in the communication range of V0 that is in the uncovered area: 1 v t vf t R ð11Þ j 0 where v1 0 is the velocity of the target vehicle in the uncovered area before selecting the 2 1 forward relay vehicle (v1 0 ¼ v0 ). Here, we get the bounds of v0 as: ð12Þ Rvfj = 2R þ dfj v1 0 Rvfj =dfj It is observed that Eqs. (4) and (12) have similar behavior and as such, satisfy the abovederived constraints.
3.3 Relay Selection and Speed Optimization of Target Vehicle Let Vbi and Vfi be backward and forward relaying vehicles that provide connectivity to V0 in the uncovered area with the RSU1 and RSU2, respectively. The backward and forward relay vehicles are selected based on the min–max communication outage time posed by them, as: U db case of Vbi ; min max 2 i ; 0 vb i v 0 U df case of Vfj : min max 2 j ; 0 v 0 v fj That is, when dbi =vbi þ dfj =vbj U=v20 , there is no outage; otherwise, the outage time is equal to U=v20 ðdbi =vbi þ dfj =vbj Þ. The vehicles i and j that provide the maximum coverage time are selected as forward and backward relays based on the above criteria. After estimating potential relay vehicles, either i or j in Scenarios 1 and 2 in Fig. 2, respectively, the V0 sends an ACM to inform the RSU. In case of Scenario 1, the ACM is directly received by the RSU1. However, when V0 is in U as in Scenario 2, the ACM received by the relay j is further forwarded to the RSU2 in order to forward the downlink communication to V0 via the relay j.
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The overall communication outage time of our bivious relay scheme is given by: U dbi dfj max 2 ; 0 for the target vehicle ð13Þ v0 vbi vfj It is assumed that dbi =vbi ¼ dfj =vfj . If, dbi U 2 and vbi v0
dbi dfj U þ 2 vbi vfj v0
exists, then the time to store data should be greater or equal to the time taken by V0 to cover the U. This indicates that no outage is experienced by the target vehicle. The following optimization problem can be formulated to find the optimum moving speeds of the target vehicle in case of bivious relays. U db df max ; 0 ð14Þ ðP1Þ:min v20 vb vf v10 v20 we have: vmin v10 vmax ; vmin v20 vmax ; Rvb Rvb v10 ; 2R þ db db vb U vb U v20 : 2R þ U þ db vb R=v10 U þ db vb R=v10 A new variable T is introduced and defined the x1 ¼ 1=v10 and x2 ¼ 1=v20 to make the problem optimizable, as: ðP10 Þ:min T x1 x2 T
ð15Þ
we have: 1 1 x1 ; vmax vmin 1 1 x2 ; vmax vmin db 2R þ db x1 ; Rvb Rvb U þ db vb R=v10 2R þ U þ db vb R=v10 x2 ; vb U vb U db db T Ux2 ; vb vb T 0: The feasible region of the above optimization problem is shown in Fig. 3. The region clearly depicts the bounds x1 and x2 . In the presence of a speed range [vmin , vmax ] (e.g. [90, 110] km/h), the feasibility region of desirable solution is within the bounds x1 and x2 (e.g.
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x2 max(x2) = 0.04
,
,
,
,
x1 max(x1) = 0.04 Fig. 3 Feasible region based on the given constraints
[0, 0] [0.04 0.033] s/m). The interior point algorithm estimates the optimal solution for these bounds of the feasible region.
4 Analytical Results and Discussion The analytical results of our proposed bivious relaying scheme are discussed in this section. Performance of our bivious relaying scheme is compared with the recently proposed scheme in [8]. The outage time experienced by the target vehicle in the uncovered area is estimated in this section with various parameters that are explained below. We consider a highway scenario with one way mobility, as shown in Fig. 2. The vehicle and the RSU can communicate within the transmission range of R = 300 m. The maximum and minimum velocity of vehicles on the highway is uniformly distributed within the range [vmin , vmax ], i.e. vmin ¼ 90 km/h and vmax ¼ 110 km/h. The analytical results are evaluated with adaptive speed or speed variation, Dv (difference between vmin and vmax ) as well as without speed variation Dv ¼ 0 of the target vehicle. In first scenario, V0 adaptively adjusts its speed to minimize the outage time and in the latter case, speed of the target vehicle remains constant. In both the cases, speed of the relaying vehicles remain constant on the highway. The variable size of the region K is also considered in the evaluation, e.g. K varies from 20 to 180 m. The vehicle arrival rate on the highway follows the Poisson Process with k vehicles per second. The average outage period is estimated after 100,000 trials by using the Monte Carlo method. Figure 4 shows the average outage time w.r.t speed variation, Dv (km/h) for varying size of K. For higher values of K, communication outage is observed to be lower than for smaller values of K. More delay occurs when the relaying vehicle tries to adjust its speed when the speed variation is large as compared to a smaller speed range, thus, showing a positive relationship between the average outage and speed variation. Average outage time for varying length of uncovered area with with the fixed speed range of [90, 110] and [95, 105] km/h is shown in Fig. 5. The behavior of both single [8] and the proposed bivious relaying schemes are analyzed. In the single relaying scheme, the communication outage experienced by the target vehicle is large. This is because V0
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becomes in outage at a time t within the uncovered area in (8). The communication outage continues until V0 enters the coverage area of RSU2. The bivious relaying scheme is proposed to provide both a backward and forward relaying mechanism. At a time, t, within the uncovered area, V0 experiences a sudden break in communication. The proposed bivious relaying scheme considers a scenario at time, ðt þ DtÞ, when one of the leading vehicle is selected as a forward relay vehicle and it is synchronized with the target vehicle by exchanging ACMs. It is observed that ðDt tÞ will be the outage duration for V0 . As V0 further moves into the uncovered area, the larger speed range of 20 km/h gives a minimal communication outage time as compared to a smaller speed range of 10 km/h. Figure 6 depicts the trend of average outage time as a function of the distance, dk (where db ¼ df ¼ dk ) for various speed ranges. The trend in the graph shows that when the vehicle that is closer to the V0 is selected as a relaying vehicle, has a smaller time to store and forward information to the target and consequently leads to the longer outage time. It is
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Fig. 7 Average outage time T (s) w.r.t uncovered region U with and without speed variation
also observed that the larger speed variation increased the communication outage time. Since mobility is a major concern in delay tolerant networks, the speed variation should be small enough to allow for smoother data transmission. The farther the relaying vehicle is from the RSU, the better the network throughput. When the distance, dk , is very small, the difference in the outages of both the single and bivious relaying is very low. As dk becomes very large, the bivious relaying scheme proves to have a better efficiency. Figure 7 shows the average outage time versus the size of the uncovered region, U, with both fixed and adaptive speeds of the target vehicle. The result also shows that the outage experienced by the target vehicle in the single relaying scheme is far more than the proposed scheme. A slight deviation in outage time between the fixed and adaptive speed scenarios has been observed. The graph also shows that the optimal size of the uncovered
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area with zero outage time achieved by the bivious relaying scheme is twice larger than the single-relaying scheme. The analysis for the average outage time for different arrival rate k of relaying vehicles is shown in Fig. 8. The arrivals of vehicles into the coverage area of the RSUs followed a Poisson process. As the same number of vehicles arrived, the proposed bivious relaying scheme experiences the minimum outage time when compared to the single relaying scheme. Smaller speed variation also results in lower communication outage as observed in Fig. 6.
5 Conclusions We have proposed a bivious relaying scheme that selects backward and forward relays to minimize the communication outage time experienced by the target vehicle in the uncovered area between two distant RSUs. The relay discovery and selection is done with no intervention of the RSUs that enables our scheme to select relays even in the uncovered area. In addition, we presented two scenarios where the target vehicle maintains a fixed speed and a second scenario where the target vehicle adjusts its moving speed based on the updated and currently discovered distance and velocity of the relaying vehicles to maintain longer connectivity. Among the relaying candidates, the vehicles that provide prolonged connectivity are selected as relays by the target vehicle. Through our bivious scheme, we observed that the target vehicle experiences 20.5–16.8 % less average outage time for varying distance between two vehicles with speed variation from 4 to 20 km/h. It also achieves 3 % less outage time for various length of the uncovered area. We are planning to employ this scheme for improving handover efficiency as well as multi-hop relaying in Vehicular networks. Acknowledgments This research was supported by the MSIP (Ministry of Science, ICT and Future Planning), Korea, under the C-ITRC (Convergence Information Technology Research Center) (IITP-2015H8601-15-1002) supervised by the IITP (Institute for Information & communications Technology Promotion).
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References 1. Yan, Z., Zhang, Z., Jiang, H., Shen, Z., & Chang, Y. (2012). Optimal traffic scheduling in vehicular delay tolerant networks. IEEE Communications Letters, 16(1), 50–53. 2. Khabbaz, M. J., Fawaz, W. F., & Assi, C. M. (2011). Probabilistic bundle relaying schemes in two-hop vehicular delay tolerant networks. IEEE Communications Letters, 15(3), 281–283. 3. Jarupan, B., & Ekici, E. (2009). Location-and delay-aware cross-layer communication in V2I multihop vehicular networks. IEEE Communication Magazine, 47(11), 112–118. 4. Yoo, J., Choi, B. S. C., & Gerla, M. (2010). An opportunistic relay protocol for vehicular road-side access with fading channels. In Proceedings of the 18th IEEE International Conference on Network Protocols (ICNP), (pp. 233–242). 5. Feteiha, M. G., Hassanein, H. S., & Kubbar, O. (2013). Opportunistic cooperation for infrastructure-torelaying-vehicles over LTE-A networks. In Proceedings of the IEEE International Conference on Communications (ICC), (pp. 6376–6380). 6. Ge, Y., Wen, S., Ang, Y., & Liang, Y. (2010). Optimal relay selection in IEEE 802.16j multihop relay vehicular networks. IEEE Transaction Vehicular Technology, 59(5), 2198–2206. 7. Chen, S., & Cheng, R. S. (2013). Signal-space-alignment-based opportunistic two-way communication via relay selection. In Proceedings of the IEEE International Conference on Communications (ICC), (pp. 5500–5504). 8. Di, W., Zhu, G., & Zhao, D. (2013). Adaptive carry-store forward scheme in two-hop vehicular delay tolerant networks. IEEE Communications Letters, 17(4), 721–724. 9. SAE Std. J2735. (2009). Dedicated Short Range Communications (DSRC) Message Set Dictionary.
Safdar Hussain Bouk was born in Larkana, Pakistan in 1977. He received the Bachelor’s degree in Computer Systems from Mehran University of Engineering and Technology, Jamshoro, Pakistan, in 2001 and Masters and Ph.D. in Engineering from the Department of Information and Computer Science, Keio University, Yokohama, Japan, in 2007 and 2010, respectively. Currently he is a working as a Post Doc Fellow at Kyungpook National University, Daegu, Korea. His research interests include Wireless Ad-hoc, Sensor Networks and Underwater Sensor Networks.
Syed Hassan Ahmed did his Bachelors in Computer Science from Kohat University of Science and Technology (KUST), Kohat, Pakistan in 2012. Later on, he joined School of Computer Science and Engineering, Kyungpook National University, Korea, where he completed his Masters in Computer Engineering in 2014. During his Bachelors and Masters, he published 20? International Journal and Conference papers in multiple topics of wireless communication. Currently he is pursuing his Ph.D. in Computer Engineering at MoNeT Lab, Kyungpook National University, Korea. He is also an IEEE/ACM member and serving several conferences and journals as a TPC and Reviewer respectively. In year 2014–2015, he won the successive Gold and Top Contributor awards in the 2nd and 3rd KNU workshop for future researchers, South Korea. His research interests include WSN, Underwater WSN, Cyber Physical Systems, VANETs and CCN in Vehicular Communications.
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S. H. Bouk et al. Babatunji Omoniwa completed his Bachelors in Engineering from Ahmadu Bello University, Nigeria. He has been working as Research Associate at National Mathematics Centre, Abuja, Nigeria, since 2012. Currently, he is pursuing his Masters in Computer Engineering from COMSATS Institute of Information Technology, Islamabad, Pakistan.
Dongkyun Kim is a professor with the Department of Computer Engineering, Kyungpook National University, Daegu, Korea. He received the B.S. degree at Kyungpook National University. He pursued his M.S. and Ph.D. degrees at Seoul National University, Korea. He was a visiting researcher at Georgia Institute of Technology, Atlanta, GA, USA. He also performed a post-doctorate program at University of California, Santa Cruz. He has been a TPC member of several IEEE conferences. He received the best paper award from the Korean Federation of Science and Technology Societies, 2002. His research interests are Ad-Hoc network, sensor network, and wireless LAN, etc.
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