ICEIC 2014, Jan. 15 - 18, 2014, Kota Kinabalu, Malaysia
Implementation and Functionality Evaluation of Maritime Point-to-Point Communication Based on NS-3 Theerayut Boonkird, Chaodit Aswakul Department of Electrical Engineering, Chulalongkorn University, Bangkok, Thailand Email:
[email protected],
[email protected] MANET research, few exist for the maritime communication context. In [1], a high speed maritime communication system has been considered with WIMAX in the Mediterranean area. In TRITON project [2], WIMAX has also been considered for the Straits of Singapore. And, in [3]-[6], the subsequent comparison has been given for the performance of various routing protocols and delay tolerance capabilities in the simulation platform of QualNet 3.9.5. In this paper, instead of relying on the licensed spectrum band as required by WIMAX, we propose to use WiFi at the unlicensed 5 GHz band. This design choice allows the system to be implemented with a low cost, high throughput capacity, and readily available system components in the market. Moreover, we use NS-3 as the implementation platform in this research because it is the open-source program with both simulation and emulation modes. NS-3 is also found the best in overall performance in [7] when compared with other MANET development platforms e.g. NS-2, omnet++, jist, simpy.
Abstract Maritime wireless ad-hoc network is the future of maritime communication. When navigators sail to the sea, they usually go together as a convoy to avoid the problem of natural causes and human factors such as occasionally severe weather conditions and piracy. In essence, the navigators need to communicate with each other in their convoy. To evaluate the system functionality, network simulators are commonly chosen method. However, simulations contain assumptions that are not necessarily justified. In this paper, we show our actual measurement results from the NS3-emulation mode of the point-to-point communication based on the real antenna settings before the future tests in maritime scenarios. Keywords: Maritime communication, NS-3.
1. Introduction
2. Wireless Point-to-Point Communication Settings
Maritime logistics is the most popular and sufficient way for the transportation of bulky goods. To guarantee smooth operations, when navigators sail to the sea, they usually go together as a convoy to avoid the problem of natural causes and human factors such as occasionally severe weather conditions and piracy. In essence, the navigators need to communicate with each other in their convoy. Communications amongst ships in a convoy are also essential for search and rescue operations. In the past, such communication methods are made possible for digital data via satellites and for voice communications via wireless broadcasting means. Satellite communications are limited in achievable performance and subject to high costs, while wireless broadcasting is relatively cheaper but its current implementation is limited to the voice mode only. To resolve these limitations, this research proposes to consider the wireless ad-hoc data communications for possible extension towards the maritime use cases. Convoy communication networks are close to mobile ad-hoc network (MANET) because the ships in the convoy can change movement directions and velocities simultaneously. While there are many literatures in
Fig. 1: Outdoor testing area In the maritime network, ships need to communicate in the long distance of at least 800 m. Therefore, ship-to-ship communication based on NS-3 has been combined with Ubiquiti Rocket M 5 with 19 dBi Sector Antenna, the transmitting power of 27 dBm in 120 horizontal degrees and 60 vertical degree beam-widths. This long-range WiFi system has been installed in two computer notebooks with
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ICEIC 2014, Jan. 15 - 18, 2014, Kota Kinabalu, Malaysia
-77 dBm, and noise level of -92 dBm. In the free space, 10 times of distances are equal to 1/100 times of signal strength or 20dB. This equates to -97 dBm at 8 km. The receiving antenna sensitivity is -96 dBm so this setting should still keep connected at 7 km as claimed in the specification of the antenna. Fig. 3 shows the average and 95% confidence interval of packet delays. The delay times are increased by only 0.5 ms at 800 m. The throughputs are relatively affected more than the delay times by the changed antenna locations.
Ubuntu 12.04. Packets have been sent in our developed NS3 code for delay time testing by using parameters in Table 1. The iperf program has been used for throughput testing by transferring the file of size 115 MBytes. At Chulalongkorn University, one computer has been set at the Communication Laboratory, Engineering 4 Building. The other computer location has been set at four locations as depicted in Fig. 1. The developed code has been used in the emulation mode with changes in layer 1 and layer 2 from simulated NS3 function to the actual communication stack via the physical ethernet interface of actual physical devices.
3. Conclusion
Table 1: Experimental parameters Mobility Model Number of packets Packet Size Interface Port Data Transmission Rate
Static 60 packets 1024 bytes WiFi ad-hoc 18888 1 packet per second
As the first step towards the actual implementation of maritime wireless ad-hoc network, this paper has shown that our NS3-based design with the long-range WiFi can reach as far as 800 m while achieving 44 Mbits/s throughputs. And the throughputs are relatively affected more than the delay times by varying the location of node. Therefore, in the ad-hoc network routing problem, if the maritime convoy communication needs a small packet transfer of such data as GPS-related information, then one can opt for sending data directly in line of sight to the furthest node in all possible routes. However, if a large data like multimedia needs be transferred, then one would need a throughput-sensitive routing algorithm that may opt for multiple-hop short-range transmissions instead. Testing of such network scenarios is currently ongoing and results will be reported in a sequel paper.
The testing time at each location is 3-5 minutes for each throughput test and 10-15 minutes for each delay test.
References [1] V. Friderikos, K. Papadaki, M. Dohler, A. Gkelias and H. Agvhami, “Linked Waters”, IEEE communications Engineer, Apr. 2005. [2] J. Pathmasuntharam, P. Konga, M. Zhou, and Y. Ge, “TRITON: High Speed Maritime Mesh Network”, in Proc. IEEE PIMRC, Sep. 2008. [3] P. Konga, H. Wanga, Y. Gea, C. Anga, S. Wena, J. Pathmasuntharama, M. Zhoub, and H. Dienb, “A Performance Comparison of Routing Protocols for Maritime Wireless Mesh Networks”, in Proc. IEEE the WCNC, Mar. 2008. [4] J. Pathmasuntharam, H. Wang, Y. Ge, C. Ang, W. Su, M. Zhou and H. Harada, “A Routing Protocol for WIMAX Based Maritime Wireless mesh network”, in Proc. IEEE VTC Spring, Apr. 2009. [5] H. Lin, Y. Gey, A. Pangz and J. Pathmasuntharamy, “Performance Study on Delay Tolerant Networks in Maritime Communication Environments”, in Proc. IEEE OCEANS, May 2010. [6] D. Yoo, G. Jin, B. Jang, L. Tuan and S. Ro, “A modified AOMDV routing protocol for maritime intership communication”, in Proc. IEEE ICT Convergence, Sep. 2011. [7] E. Weingartner, H. Lehn and K.Wehrle, “A performance comparison of recent network simulators”, in Proc. IEEE ICC, Jun. 2009.
Fig.2: Received signal strength and throughput
Fig.3: Average delay with 95% confidence interval Fig. 2 shows the received signal strength and throughput of packet. The result shows that our NS3based design with the long-range WiFi antenna can reach as far as 800 m at 44 Mbits/s, received signal strength of
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