WO2010030166A1

WO2010030166A1 - A method to speed mobile ipv6 handovers between interconnected wireless communications terminals

Info

Publication number: WO2010030166A1
Application number: PCT/MY2009/000139
Authority: WO
Inventors: Shariq Hasseb; Muhammad Faheem Mohd Ezani; Mohd Ariff Abdullah; Gopinath Rao
Original assignee: Mimos Berhad
Priority date: 2008-09-15
Filing date: 2009-09-09
Publication date: 2010-03-18
Also published as: MY157975A

Abstract

A method to speed Mobile IPv6 handovers between interconnected terminals in a wireless communication is provided herewith, wherein the connection to the future terminal is made prior to disconnecting the connection with present terminal.

Description

A Method To Speed Mobile IPv6 Handovers Between Interconnected Wireless

Communications Terminals

Field of Invention

This application relates to a fast Mobile IPv6 handover method for in wireless communication.

Background of Invention

Mobile Internet Protocol version 6 (IPv6) allows an IPv6 node to be mobile — to arbitrarily change its location on the IPv6 Internet — and still maintain existing connections. Connection maintenance for mobile nodes is not done by modifying connection-oriented protocols such as TCP, but by handling the change of addresses at the Internet layer using Mobile IPv6 messages and options and processes that ensure the correct delivery of data regardless of the mobile node's location.

A typical wireless communication based Mobile IPv6 scenario is depicted in figure 1. In this protocol when a mobile node decides to move to a new network due to the deterioration hi signal in the present network, the mobile node will experience a indefinite handoff interruption that can last about 2 to 10 seconds, hi real time applications this duration of interruption can be easily observed by end users as a break in communications. This is because when a mobile node detaches itself from its current network and attaches itself to a new network it has to wait a random amount of time and request for an IPv6 prefix advertisement.

Further to the above, the present protocol faces other problems such as a. Macro mobility nature of Mobile IPv6 protocol where Mobile nodes are assumed to travel long distances and thus the Mobile IPv6 protocol was designed to solve macro mobility, while in reality the Mobile nodes almost always hop to the next neighboring coverage b. Mobile IPv6 deployment architecture complexity, where Mobile IPv6 protocol proposes the use of a Home Agent as an external entity which adds larger inter packet delays, thus increasing the complexity of the network and incur higher cost of deployment c. Layer-2 triggers for mobile nodes which are currently based only on signal strength.

Therefore, it appears that there is a need for a new Mobile IPv6 protocol which will enables faster and smoother handovers.

Summary of Invention

The primary object of the present invention is to provide a method to speed Mobile IPv6 handovers between interconnected terminals by means of

a. A faster and more efficient handoff algorithm to reside over wireless communications terminals b. A hybrid solution so that there is compatibility for both macro and micro mobility c. Build the Home Agent as a service on each terminals to reduce the network traversal time d. A more efficient Layer-2 trigger to initiate network movement

Description of Drawings

Figure 1 Typical Mobile IPv6 scenario in wireless communication

Figure 2 Message flow diagram of wireless communication Mobile IPv6

Figure 3 Modified neighbor advertisement message

Figure 4 Modified router advertisement message

Figure 5 Exemplary scenario

Figure 6 Message flow diagram Figure 7 Flow chart of protocol

Detailed Description

The flow chart in Figure 7 gives a general view of the present invention which will be discussed in detail now. In the following description, detailed description of the known functions and configurations have been omitted for clarity and conciseness.

In the present invention the wireless communications terminals are defined as wireless communication terminal having WiFi front end and WiMax Back end or WiFi front end and HSDPA or Ethernet backend .

The method of speed Mobile IPv6 handovers between interconnected wireless communications terminals proposed by the present invention is implemented by the following phases:

Bootstrap Phase

In this phase each wireless communications terminal informs its neighboring wireless communications terminal of its presence by means of a modified neighborhood advertisement message as illustrated in Figure 3. The advertisement message contains a wireless communication flag set and also an advertisement lifetime, CPEs Media Access Control (MAC) address, built in WiFi modules' MAC address, WiFi Modules' IPv6 address and WiFi modules' ESSID in the option field. This message will be re-advertised compulsorily by the wireless communications terminal at the expiration of the advertisement lifetime or if there has been any changes in the addresses.

Information Building Phase In this phase each terminal will be equipped with a wireless communications terminal table, which is dynamically updateable and contains the information of the neighboring terminals

Information dissemination phase

This phase contains the following sequence: i. A Mobile Node sends out a router solicitation message requesting for an

IPv6 prefix, each time it connects to a terminal ϋ. The terminal responds with a modified router advertisement shown in

Figure 4. iii. The Mobile Node then generates a its own wireless communications terminal Table and IPv6 address from the information found in the modified router advertisement iv. The router advertisement message subsequent to the first modified router advertisement message need not contain the full wireless communications terminal table because it only needs to reflect the changes made to the wireless communications terminal table.

Movement phase

In this phase a Mobile Node volunteers to move to the next terminal when it detects i. a weak signal from the current terminal; or ii. an increasing rate of frame errors during transmission; or iii. a reduced bandwidth and a second signal from a neighboring terminal

Prior to moving the Mobile Node configures it future IPv6 address from the information present in the wireless communications terminal table. It uses this address to send a

Binding Update to its Home Agent. The Mobile Node then proceeds to detach itself from the present terminal and attach itself to the new terminal. The Home Agent then assumes that the Mobile Node has moved and forwards the binding update and data packets to the new location of the Mobile Node.

Buffering Phase hi this phase each terminal stores the forwarded packets received from the Home Agent within the fixed sized buffer it is equipped with.

Re-attaching phase

In this phase the Mobile Node that has detached itself from its previous terminal in the Movement Phase, attaches itself to the new network and sends out a neighbor advertisement to announce its connection to the new network. At this point the terminal stops buffering and forwards the buffered packets to the Mobile Packet.

Backward Compatibility

This phase only occurs when the Mobile Node does not have any information of the new terminal in its wireless communications terminal table. In this instance the Mobile then abandons the fast handoff procedure and returns to the standard Mobile IPv6 procedure. This phase can also be utilized in hybrid scenario where intra-site movements use fast handover procedure while inter-site movements will use the standard Mobile IPv6

A example of the present invention can be seen in figure 5. From the figure it becomes clear that step no.5 i.e. the mobile node decides to move and sends a binding update, forms the most important part of the invention. This steps illustrates the 'make before break' strategy employed by this invention. By means of this strategy the handover delay can be significantly reduces because the new terminal is prepared to accept the Mobile Node even before the connection between the Mobile Node and the prior terminal is broken. The only delay that can be observed is the Layer-2 attachment delay which is about 50-200 ms.

Claims

1. A method to allow a more prompt handover in Mobile IPv6 in a network by means of a mobile unit determining the future terminal that the mobile unit is to attach itself before detaching itself from its current terminal comprising the steps of: determining the future terminal address of the mobile unit from the wireless communications terminal table and sending a binding update to the mobile unit's Home Agent detaching the mobile unit for the mobile unit's present terminal and attaching the mobile unit to a new terminal forwarding the binding updates and data packets from the Home Agent to the new terminal storing packets received from Home Agent within the terminal's fixed sized buffer sending out neighbor advertisement to announce the mobile unit's new location forwarding the buffered packets to mobile unit upon receiving the terminal's neighbor advertisement.

2. A method according to claim 1, wherein the mobile unit will prepare to detach itself from the its current terminal when there is a weak signal from the current terminal, an increasing rate in frame errors during transmission or a reduced bandwidth and a second signal is received from a neighboring terminal.

3. A method according to claim 1, where each terminal contains a wireless communications terminal table which consists of information of neighboring terminals.

4. A method according to claim 1 , wherein each mobile node contains a wireless communications terminal table.