Multiplex communications – Communication techniques for information carried in plural... – Adaptive
Reexamination Certificate
2001-02-01
2004-06-08
Nguyen, Chau (Department: 2663)
Multiplex communications
Communication techniques for information carried in plural...
Adaptive
Reexamination Certificate
active
06747993
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to a method and system for adjusting a communication timer in a communication network, and more particularly to a method and apparatus for adjusting an acknowledgment timer for a communication network when the data transfer rate of the system has changed.
Communication networks such as wide area networks (WANs) and local area networks (LANs) rely heavily on the efficient transfer of data from one computer or networked component to another. This efficiency can be greatly affected by the number of users accessing the system at one time. For example, in a wireless telecommunications network the data transfer rate of the entire network typically decreases as the number of users using the network (or traffic) increases. In terms of data transfer speed, the network is no longer operating as efficiently for each user. This decrease in the data transfer rate can disrupt various systems within the communication network and further cause the system to run even less efficiently.
In typical wireless telecommunication networks, the networked components are comprised of base and mobile stations which communicate with each other using a radio link protocol (RLP). Several industry standards are available for implementing such networks and provide generalized functions/features the various systems should follow. For example, IS-95 is a digital code division multiple access (CDMA) protocol standard for U.S. wireless networks set forth by the Telecommunications Industry Association (TIA) and the Electronic Industries Alliance (EIA) in an effort to make wireless network systems somewhat uniform in the US. This standard is repeatedly evaluated and improved on by members of the telecommunications industry.
Today, these groups are implementing third generation CDMA systems (often referred to as CDMA2000 or IS-95-C) which use an octet based RLP to transmit packets of data or information between the base station and the mobile station, and vice versa. The protocol divides the packets into frames for data transmission over communication channels and attaches headers and trailers to each packet and frame to indicate the beginning and end of the packet/frame, and to indicate the sequence number or order in which the packet/frame is to be received in order to recover the original message transmitted. Since the packets are of variable size, some frames may contain only portions of a packet, while others may contain multiple packets for transmission. According to several standards, a frame is typically generated by the RLP every 20 milliseconds (ms). The primary benefit accompanying this new generation industry standard is that higher data transfer rates can be obtained within the network, allowing for the transmission of high speed data at various data transfer rates. Even so, as traffic on these networks continually increases, the data transfer rates will decrease, resulting in undesirable disruption of various systems within the communication network.
For example, several communication networks have acknowledgment systems implemented to confirm receipt and/or failure of receipt of information from one component to another. The idea behind such systems is to keep the network operating efficiently while at the same time ensuring that the communications are being accurately made. In other words, using cellular telephone networks as an example, the acknowledgment system avoids having a user wait on his or her phone for an unduly long period, when it is likely that the voice data his or her unit is awaiting will not be received.
The acknowledgment systems allow for the transmission of high speed data, and rely on timers for determining whether an acknowledgment signal has been received and/or responded to. These timers do not account for changes in the data transfer rate of the network, and are setup to interpret a response to the acknowledgment signal that is delayed by a predetermined amount as a failure to respond irrespective of current data transfer rates in the system. This failure typically causes a second or third acknowledgment signal to be sent, which may not only be unnecessary, but also increases the traffic over the network and further reduces the efficiency of the entire system. The failure may also cause the acknowledgment system to abort efforts in determining whether an acknowledgment signal has been received and/or responded to.
One type of acknowledgment system implemented in computer and telecommunication networks involves polling each component to which information has been sent in order to determine if the information has been received. This can be accomplished by having the components that have received information transmit an ACK (“acknowledge”) signal upon receipt of the information. Another type of acknowledgment system implemented in networks involves having components report the fact that they did not receive the information sent to them (e.g., the information was lost, incomplete, or corrupted). This can be accomplished by having the components that have not received the sent information transmit a NAK (negative acknowledge) signal indicating that the information must be re-transmitted. Out of the two systems, the latter NAK system is preferred because it allows for more efficient network operations since only the components needing retransmission of data have to transmit an acknowledgment, whereas with the ACK system, both the components needing retransmission of data and those that do not have to transmit signals.
As mentioned, these acknowledgment systems use timers to determine whether signals have been received by the desired network components and/or to re-transmit signals if need be. For example, the receiving component or network component responsible for transmitting the acknowledgment signal (either ACK or NAK) typically starts an acknowledgment timer upon transmission of the acknowledgment signal. The purpose for the timer is to account for situations in which the acknowledgment signal sent by the receiving component has not been received by the transmitting component or network component responsible for responding to the acknowledgment signal. According to the standardized systems mentioned above, if no signal or response is heard by the receiving component within the predetermined time period of the acknowledgment timer, the receiving component will assume that the acknowledgment signal was lost and will re-transmit the acknowledgment signal and restart the acknowledgment timer. Again, if no signal or response is heard within the predetermined time period of the acknowledgment timer, the receiving component will retransmit the acknowledgment signal a third and final time, and restart the acknowledgment timer. At this point, the timer is often referred to as an abort timer. If the acknowledgment/abort timer expires without the receiving component hearing a response to the third acknowledgment signal, the receiving component will abort its acknowledgment efforts and either continue or drop communications with the transmitting component.
For example, if a NAK system is employed in the telecommunications network discussed above, and a packet/frame is not received by the desired network receiving component, the receiving component in the network will transmit a NAK signal requesting retransmission of the missing packet/frame. Once the NAK signal is transmitted, the receiving component (which could be a base station or a mobile station) starts a retransmission or acknowledgment timer that expires after a predetermined amount of time. Again, the purpose for the timer is to make the network more efficient by accounting for situations in which the NAK signal or NAK request Is not received by the transmitting component (e.g., the NAK signal itself was lost, incomplete, or corrupted). More particularly, the receiving component will wait the predetermined amount of time, and if no response to its NAK signal is received, the receiving component will presume that a problem occurred with respect to the earlier NAK signal.
Jacobs Jeffrey K.
Juntima Nittaya
Motorola Inc.
Nguyen Chau
LandOfFree
Method and apparatus for adjusting a communication timer in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for adjusting a communication timer in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for adjusting a communication timer in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3296504