Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1996-10-31
2001-04-17
Dolinar, Andrew M. (Department: 3747)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S445000
Reexamination Certificate
active
06219547
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to apparatus and method for communications and more specifically to mobile radio data communications systems.
2. Description of the Related Art
Circuit switching is inefficient for bursty mobile data services such as facsimile (fax), electronic mail (email), and short messaging. First generation cellular systems that provide data communications using circuit switching have difficulty passing modem signals through the audio filters of receivers designed for analog air-interfaces. Inevitably, voice filtering must be deactivated when data is transmitted over first generation cellular networks, and a dedicated data link must be established over the common air-interface. The demand for packet data services has, until recently, been significantly less than the demand for voice services, and first generation subscriber equipment design has focused almost solely on voice-only cellular communications. The cellular digital packet data (CDPD) standard was developed to coexist with the conventional voice-only cellular system.
However, numerous shortcomings exist with CDPD systems. One such shortcoming occurs when a mobile end-station (M-ES) is roaming away from the area covered by its home mobile data intermediate station (MD-IS). Much time, overhead processing and routing resources are expended in forwarding the data to the MD-IS serving the area in which the M-ES is now visiting.
There is accordingly a need for improvements in the system and method for routing digital packet data to a roaming M-ES in a Cellular Digital Packet Data network in order to solve or ameliorate the above-described problem.
SUMMARY OF THE INVENTION
Cellular Digital Packet Data (CDPD) is a data service for first and second generation U.S. cellular systems and uses a full 30 kHz AMPS channel on a shared basis. CDPD provides mobile packet data connectivity to existing data networks and other cellular systems without any additional bandwidth requirements. CDPD may directly overlay with existing cellular infrastructure and use existing base station equipment, making it simple and inexpensive to install, or it may be incorporated within new systems. Furthermore, CDPD does not have to use the Mobile Switching Center (MSC), but rather may have its own traffic routing capabilities. CDPD occupies voice channels purely on a secondary, noninterfering basis, and packet channels are dynamically assigned (hopped) to different cellular voice channels as they become vacant, so the CDPD radio channel varies with time.
According to a specific implementation of our invention, routing of data to an intended recipient roaming mobile end station (M-ES) within a CDPD network is facilitated by determining if the roaming station is within the same geographic area of the originating data source. If the intended recipient roaming mobile end station is within the same geographic area as verified by interrogation of the local mobile data interface station, then data is sent directly to the intended mobile end station without transmission to the intended mobile end station's home mobile data interface station.
If the intended recipient mobile end station is not currently located within the same geographic area served by the originating data source, then the data is transmitted to the mobile end station's home Mobile data intermediate station where the last known location of the roaming mobile end station is stored and then on to the appropriate mobile data intermediate station corresponding to the last known location.
Advantages of the current invention include reduced processing time, less network overhead in transferring data messages throughout the network and a reduction in congestion due to no longer needing to encapsulate and decapsulate data into and from data packets for transmission.
The foregoing features together with certain other features described hereinafter enable the overall system to have properties differing not just by a matter of degree from any related art, but offering an order of magnitude more efficient use of processing time and resources.
Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the apparatus and method according to the invention and, together with the description, serve to explain the principles of the invention.
REFERENCES:
patent: 5325362 (1994-06-01), Aziz
patent: 5400338 (1995-03-01), Flammer, III
patent: 5533029 (1996-07-01), Gardner
patent: 399612 (1990-11-01), None
patent: 16330 (1995-06-01), None
patent: WO 95/16330 (1995-06-01), None
Myles A., et al., “A Mobile Host Protocol Supporting Route Optimization and Authentication,” IEEE Journal on Selected Areas in Communications, vol. 13, No. 5, Jun. 1, 1995, pp. 839-849.
Parsa K: “The Mobitex* Packet-Switched Radio Data System,” IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Oct. 19, 1992, pp. 534-538.
Haemaelaeinen J, et al., “Proposed Operation of GSM Packet Radio Networks,” IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, vol. 1, Sep. 27, 1995, pp. 372-377.
Myles A. et al., “A Mobile Host Protocol Supporting Route Optimization and Authentication,” IEEE Journal on Selected Areas in Communications, vol. 13, No. 5, Jun. 1, 1995, pp. 839-849.
Akhtar Haseeb
Qaddoura Emad A.
Dolinar Andrew M.
Hunton and Williams
Nortel Networks Corporation
LandOfFree
System and method for routing in a cellular digital packet... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for routing in a cellular digital packet..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for routing in a cellular digital packet... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2467165