Seamless Mobility

Publications

• S.K. Lee, K. Sriram, K. Kim, Y.H. Kim, and N. Golmie, Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks, IEEE Transactions on Vehicular Technology, Vol. 58, No. 2, February 2009, pp. 865-881.

• S. Yoo, D. Cypher and N. Golmie, Predictive Handover Mechanism based on Required Time Estimation in Heterogeneous Wireless Networks, Military Communications Conference (MILCOM) 2008, San Diego, CA, 17-19 Nov. 2008.
• A. Izquierdo, N. golmie, K. Hoeper and L. Chen, Using the EAP Framework for Fast Media Independent Handover Authentication Wireless Internet Conference (WiCON) 2008, Maui, HI, November 17-19, 2008.
• R. Rouil, N. Golmie and N. Montavont, IEEE 802.21 Transport Solution Using Cross-Layer Optimized Stream Control Transmission Protocol, IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications, 2008. PIMRC 2008. 15-18 Sept. 2008, pp. 1-5.
• S. Yoo, N. Golmie and H. Xu, QoS-Aware Channel Scanning for IEEE 802.11 Wireless LAN, IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications, 2008. PIMRC 2008. 15-18 Sept. 2008, pp. 1-6.
• S. Yoo, D. Cypher, and N. Golmie, Timely Effective Handover Mechanism in Heterogeneous Wireless Networks , Proceedings of the Springer Wireless Personal Communications special issue on 'Resource and Mobility Management and Cross-Layer Design for the Support of Multimedia Services in Heterogeneous Emerging Wireless Networks'
• D. Griffith, R. Rouil, and N. Golmie, "Performance Metrics for IEEE 802.21 Media Independent Handover (MIH) Signaling" , Proceedings of the Springer Wireless Personal Communications special issue on "Resource and Mobility Management and Cross-Layer Design for the Support of Multimedia Services in Heterogeneous Emerging Wireless Networks"
• S. Yoo, D. Cypher, and N. Golmie, "Predictive Link Trigger Mechanism for Seamless Handovers in Heterogeneous Wireless Networks" Published online at www3.interscience.wiley.com, Wireless Communications and Mobile Computing.

• N. Golmie, "Cross-layer mobility management in support of seamless handovers" Globecom 2007 D&D Forum, November 28, 2007
• S. Yoo, D. Cypher, and N. Golmie, "LMS Predictive Link Triggering for Seamless Handovers in Heterogeneous Wireless Networks" Military Communications Conference (MILCOM) 2007, Orlando, FL, October 29-31, 2007.

• R. Rouil and N. Golmie, "Adaptive Channel Scanning for IEEE 802.16e," Proceedings of 25th Annual Military Communications Conference (MILCOM 2006), Washington, D.C., October 23-25, 2006.
  • Presentation for Adaptive Channel Scanning for IEEE 802.16e
• S. Woon, N. Golmie, A. Sekercioglu, "Effective Link Triggers to Improve Handover Performance," Proceedings of 17th Annual IEEE Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC'06), Helsinki, Finland, September 11-14, 2006.
• S. Lee, N. Golmie, "Power-Efficient Interface Selection Scheme using Paging of WWAN for WLAN in Heterogeneous Wireless Networks," Proceedings of IEEE International Conference on Communications, Istanbul, Turkey, June 12-15, 2006.
• D. Cypher, N. Chevrollier, N. Montavont, and N. Golmie, "Prevailing over Wires in Healthcare Environments: Benefits and Challenges," IEEE Communications Magazine, Vol. 44, No. 4, pp. 56-63, April 2006.

• N. Chevrollier, N. Montavont and N. Golmie, "Handovers and Interference Mitigation in Healthcare Environments," Proceedings of the IEEE Military Communications Conference (MILCOM 2005), October 17-20, 2005.
• N. Chevrollier and N. Golmie, "On the Use of Wireless Network Technologies in Healthcare Environments," Proceedings of the fifth IEEE workshop on Applications and Services in Wireless Networks (ASWN 2005), June 2005 Paris, France, pp. 147-152.
• N. Golmie, D. Cypher, and O. Rebala, "Performance Analysis of Low Rate Wireless Technologies for Medical Applications," Computer Communications, Volume 28, Number 10, June 2005, pp. 1255-1275.
  See related
• Seamless and Secure Mobility (presentation) given at the 9th DOD Annual Information Assurance Workshop in Philadelphia, PA, 7-10, February, 2005.

• "Seamless Mobility in WiMax" presentation (.ppt) given to the WiMax Forum, Hawaii, January, 2007
  • Video for mobility in IEEE 802.16/802.16e networks (.avi)
  • Video for mobility in heterogeneous wireless networks (.avi)

Contributions to Standard Developing Organizations (SDOs)

Tools

Release information

A simulation platform based on NS-2 is being developed in order to leverage publicly available modules for several wireless and wired technologies. IEEE 802.3 (Ethernet), IEEE 802.11b (WLAN), IEEE 802.15.1 (Bluetooth), and UMTS have been developed for various previous releases of NS-2, but have not been integrated to run jointly in a single simulation environment. By integrating various modules into a single platform, we make it possible to simulate heterogeneous environments that incorporate a variety of access networking technologies.

• 10/01/2006: release of the IEEE 802.16 model developed for NS-2.
• 01/23/2007: release of the mobility package developed for NS-2.
• 02/28/2007: update of mobility package. TCL scripts have been udpated according to new model.
  Use the request form to download the file.
• 04/30/2007: update of the IEEE 802.16 model.
  Note: contains patch for ns-2.31. See documentation for the list of modifications.
  Use the request form to download the file.
• 10/04/2007: update of documentation (version 1.2) for the IEEE 802.16 model.

Documentation

Description of software modules

	IEEE 802.16 module	Mobility extensions
Overview	An overview of the model is given in the following presentation
Installation	The release file available for the IEEE 802.16 module for NS-2 contains instructions to install the module.	Instructions for installing the mobility package for NS-2.
User and design information	The IEEE 802.16 model documentation describes the available features, the TCL configuration, and design aspects of the implementation. A description of the IEEE 802.16 package classes	Modifications to the MAC IEEE 802.11 model Documentation on the IEEE 802.21 implementation Documentation on the Neighbor Discovery module
Updates and bug fixes	Problem: Duplicate variable declarations The variable "Packet *pktBuf_;" is declared in both mac802_16.h and mac802_16SS.h Solution: remove the declaration in mac802_16SS.h	Problem: MAC 802.11 stalls after scanning In certain situations, the MAC 802.11 will lock its transmission after a scan. Solution: add the following code in your mac-802_11.cc on lines 3852 and 3915: &nbsp&nbsp&nbsp //resume transmission &nbsp&nbsp&nbsp if (mhBackoff_.busy() == 0 && mhDefer_.busy() == 0 && mhSend_.busy() == 0) { &nbsp&nbsp&nbsp tx_resume (); &nbsp&nbsp&nbsp } Problem: Error message during compilation: hsntg/nd.cc: In constructor `NDAgent::NDAgent()': hsntg/nd.cc:127: error: call of overloaded `bind(const char[17], uint32_t*)' is ambiguous Solution: The error may occur depending on the version of gcc used. Replace bind("prefix_lifetime_", &prefix_lifetime_); with bind("prefix_lifetime_", (unsigned int*) &prefix_lifetime_);

Frequently Asked Questions (FAQs)

IEEE 802.16 model for NS-2

1. Q: What does "bash: ns: command not found" mean?
   A: The NS-2 simulator is not properly installed/compiled. Execute "./configure; make clean; make" from the ns-2.29 directory.
2. Q: What does invalid command name "Phy/WirelessPhy/OFDM" while executing "Phy/WirelessPhy/OFDM set g_0" mean?
   A: The OFDM class is unknown to NS. This means the code has not been recompiled. Execute "./configure; make clean; make" from the ns-2.29 directory.
3. Q: What does invalid command name "Mac/802_16" while executing "Mac/802_16 set debug_ 0" mean?
   A: The Mac/802_16 class is unknown to NS. This means the code has not been recompiled. Execute "./configure; make clean; make" from the ns-2.29 directory.
4. Q: Compilation error "NeighborEntry already defined".
   A: A class with the same name is defined in the diffusion3 subdirectory. Rename the class NeighborEntry to WimaxNeighborEntry where used.
   Note: The updated pre-release contains the modification.
5. Q: Does the current model support class of service (UGS, RTPS, NRTPS and BE)?
   A: No. Though the architecture defines the structures to use it, the current scheduler does not make use of it.
6. Q: What scheduler is implemented?
   A: The scheduler allocates downlink bandwidth first according to pending traffic. Next, the contention periods are allocated in the uplink bandwidth. The rest of the uplink bandwidth is then allocated to one MS (The MS is picked in a Round Robin fashion). Currently the BS does not consider bandwidth requests from the MSs.
7. Q: How to set the -DDEBUG_WIMAX switch?
   A: Look for the line starting with "DEFINE = -DTCP_DELAY_BIND_ALL" and add the -DDEBUG_WIMAX.
8. Q: How to set the datarate?
   A: Unlike the 802.11 implementation, the datarate is not something set in TCL. Since each burst can use a different modulation and therefore have different datarates, we opted for a dynamic calculation of the datarate. By setting the frequency bandwidth, cyclic prefix and the modulation, the datarate will change. The scripts located in tcl/wimax/datarate/ show the maximum throughput achieved with frequency bandwitdh of 7MHz.

Mobility package for NS-2

1. Q: The scripts are not running in the pre-release dated 01/27/07. What is the problem?
   A: The model is under development. Therefore some older scripts may not have been updated. Download the new release with udpated examples.
2. Q: How do I install the mobility package?
   A: The mobility package contains a complete ns-2.29 directory. Delete the default ns-2.29 directory and replace it with the one provided in the compressed file.
3. Q: Segmentation fault when using older scripts with the new model.
   A: The structures have changed for the MAC and classifer classes. The scripts have to be updated.