Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
1999-07-28
2001-11-20
Le, Thanh Cong (Department: 2684)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
C455S514000
Reexamination Certificate
active
06321093
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to wireless communication networks and, more specifically, to a system for controlling priority calls in a wireless network.
BACKGROUND OF THE INVENTION
In 1996, more than 75 million people worldwide used cellular telephones. Reliable predictions indicate that there will be over 300 million cellular telephone customers by the year 2000. Within the United States, cellular service is offered not only by dedicated cellular service providers, but also by the regional Bell companies, such as U.S. West, Bell Atlantic and Southwestern Bell, and the national long distance companies, such as AT&T and Sprint. The enhanced competition has driven the price of cellular service down to the point where it is affordable to a large segment of the population.
Wireless subscribers use a wide variety of wireless devices, including cellular phones, personal communication services (PCS) devices, and wireless modem-equipped personal computer (PCs), among others. The large number of subscribers and the many applications for wireless communications have increased wireless traffic to the point that communication channels are frequently unavailable when a subscriber attempts to initiate a call in a wireless communication system.
When a subscriber is unable to access a channel when the subscriber initiates a call, the wireless system may “reserve” the next available channel for the missed call and then initiate a return call to the subscriber's device when the channel is finally available. In such a system, the wireless system may also assign a priority level to each missed call in order to service higher priority calls first. For example, 911 calls (emergency calls) may be assigned the highest priority and premium subscribers who pay a higher service fee may be assigned a higher priority level than regular subscribers who pay the standard service fee. Calls having a higher priority level are served before lower priority level calls when the next channel comes available. As between two calls having the same priority level, the calls are served in the order received (i.e., chronological) when the next channel comes available. However, if a subscriber moves from one base station coverage area to another, there is no way to maintain the original priority level of that subscriber's missed call with respect to the pending missed calls in the new coverage area.
There is therefore a need in the art for a wireless communication system that is able to maintain the proper priority level of a missed call in a new coverage area when a subscriber moves from a first coverage area in which the call was missed to a new coverage area. In particular, there is a need in the art for an improved wireless communication system that tracks the priority levels of all missed calls in a plurality of base station coverage areas and which maintains priority levels of missed calls on a system-wide basis, rather than within individual base station coverage areas.
SUMMARY OF THE INVENTION
To overcome the above-described shortcomings of the prior art, there is disclosed a wireless communications network in which a group of base stations are served by a mobile switching center that maintains a master data record for all missed calls from mobile devices in all of the base station coverage areas. Missed call data are stored in different priority level queues in each of the bases stations. When a call is missed in a first base station coverage area, a time stamp for the missed call is stored in the mobile switching center. Alternatively, the mobile switching center can store a sequential number associated with each missed call without regard to the base station from which it is received. In this manner, each missed call has a unique sequence number assigned to it.
If the mobile device moves into a second base station coverage area, the mobile device re-originates the missed call. The second base station receives from the mobile switching center the priority level of the call re-originated by the mobile device and retrieves the time stamp or unique sequence number from the mobile switching center. If the second base station does not have a traffic channel available, the second base station can put the missed call in the proper priority level queue and, within that proper priority level queue, can determine the priority of the missed call relative to the pre-existing missed calls already in the priority level queue. Missed calls having older time stamps or lower sequence numbers are of higher priority and are placed higher in the appropriate priority level queue. In this manner, priority can be maintained across the entire wireless network, not merely within individual base station coverage areas.
Accordingly, there is provided, for use in a wireless communication network comprising a plurality of base stations capable of communicating with a plurality of mobile devices, an apparatus for maintaining a priority of a missed call from a first mobile device being served by a first base station. In an advantageous embodiment, the apparatus comprises 1) a central controller capable of receiving from a first base station a first message indicating that the first base station is unable to service a pending call from a selected one of the plurality of mobile devices and assigning to the pending missed call a priority indicia; 2) a memory capable of storing the priority indicia; and 3) a priority indicia controller capable of sending the priority indicia to a second base station in response to a receipt from the second base station of a second message indicating that the selected one of the plurality of mobile devices is being serviced by the second base station, wherein the second base station uses the priority indicia to maintain the priority of the pending missed call with respect to at least one pre-existing pending missed calls being serviced by the second base station.
According to one embodiment of the present invention, the central controller is disposed in the first base station.
According to another embodiment of the present invention, the priority indicia controller is disposed in a mobile switching center of the wireless communication network.
According to still another embodiment of the present invention, the memory comprises a plurality of queues, wherein each of the queues is capable of storing call information associated with calls having a similar priority level.
According to yet another embodiment of the present invention, the calls having a similar priority level are serviced by the first base station on a first-come, first-served basis.
According to a further embodiment of the present invention, the plurality of queues comprises an emergency queue for storing priority indicia associated with emergency calls.
According to a still further embodiment of the present invention, the plurality of queues comprises a preferred queue for storing priority indicia associated with calls received from subscribers belonging to a premium class of service.
According to a yet further embodiment of the present invention, the priority indicia comprises a time stamp associated with the pending missed call.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
Before undertaking the DETAILED DESCRIPTION, it may be advantageous to set forth definitions of certain words and phrases use
Cong Le Thanh
Han John C.
Samsung Electronics Co,. Ltd.
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