The present invention relates generally to radiotelephone communications and, more particularly, to a system and method for adapting the portable computer of an existing mobile station so as to be instantly capable of supporting packet-switched connections, e.g., GPRS.
When the personal computer market exploded during the early 1980's, these computers were used to perform individual, isolated tasks without communication with other computers except through the exchange of floppy disks. However, as the personal computer market developed, the need for communication between personal computers grew. One communication technology that rose to the forefront was modem technology. By connecting modems to their personal computers, users had the capability of directly transferring data between and communicating in real time with other communication devices. Such data transfers were commonly made through either a direct connection between the personal computers or via a telephone connection.
Certain standards have evolved for communicating between a computer and its attached modem. Physical links between these device are generally made through a serial or parallel communications port. One skilled in the art will appreciate that the computer sends certain commands through the physical link to the modem and, as a result, the modem returns certain responses. The de facto standard for these commands is the Hayes Microcomputer Products™ “AT” command set. This command set is well known in the art and includes such commands as the ‘D’ (Dial) command. The ‘D’ command requests the modem to dial a telephone number supplied in a dial string, e.g., ‘ATD18075552691’. Such a command is hence interpreted by the modem as a request to set up a circuit-switched call to the indicated number.
While intercommunication between personal computers was on the rise, another need became evident, i.e., the need to communicate with remote systems through cellular connections. As technology became more sophisticated, personal computers were designed to be increasingly smaller. With the advent of laptop and notebook computers in the early 1990's, computer portability became possible. Portable computers allowed users to carry the computers from city to city, state to state, and even country to country. However, a problem still existed; while stationary machines can be conveniently connected to communication networks via a telephone line, portable computers lacked this capability during times when normal phone connections were not available. As a result, attempts have been made to combine cellular telephone technology with these portable devices in order to allow for distant communications. By connecting a portable computer (e.g., a laptop computer) to a cellular phone, one can access a telephone network in generally the same way as by directly hooking the computer to a telephone wall outlet. One skilled in the art will appreciate that the combination of a portable computer and cellular phone may be referred to as a “mobile station”.
The cellular industry, by which these mobile stations communicate, has made phenomenal strides in commercial operations in the United States as well as the rest of the world. Growth in major metropolitan areas has far exceeded expectations and is rapidly outstripping system capacity.
Throughout the world, one important step in the advancement of radio communication systems is the change from analog to digital transmission. Equally significant is the choice of an effective digital transmission scheme for implementing the next generation technology, e.g., time division multiple access (TDMA) or code division multiple access (CDMA). Furthermore, it is widely believed that the first generation of Personal Communication Networks (PCNs), employing low cost, pocket-sized, cordless telephones that can be carried comfortably and used to make or receive calls in the home, office, street, car, etc., will be provided by, for example, cellular carriers using the next generation digital cellular system infrastructure.
To provide an acceptable level of equipment compatibility, standards have been created in various regions of the world. For example, analog standards such as AMPS (Advanced Mobile Phone System), NMT (Nordic Mobile Telephone) and ETACS and digital standards such as D-AMPS (e.g., as specified in EIA/TIA-IS-54-B and IS-136) and GSM (Global System for Mobile Communications adopted by ETSI) have been promulgated to standardize design criteria for radio communication systems.
Continued advancements in the field of cellular technology, as well as other types of radiotelephone communications, have permitted the introduction of new services and new forms of communications. For instance, proposals have been set forth to provide existing cellular, and other communication networks, with the capability of communicating packet data. Unlike circuit-switched connections, packet-switched connections allow multiple users to share the same physical channel by providing routing information in a header attached to each payload of data. By sharing the same physical channel among multiple users, packet-switched connections tend to optimize bandwidth utilization for the relatively bursty data communication applications.
One such packet data system is the General Packet Radio Service (GPRS). A comprehensive description of GPRS is provided in the GSM Specification, GSM 03.60, version 6.1.0 which is incorporated by reference herein. GPRS uses a packet-mode technique to transfer high-speed and low-speed data and signalling in an efficient manner. As a result, a mobile station which supports GPRS would be capable of sending and receiving packet data.
Many different types of services have been implemented which benefit from the use of data packet communications. Such services include, for example, messaging services (e.g., electronic mail or facsimile transmissions), database retrieval services (e.g., retrieval of information from the World Wide Web) and distribution services (e.g., news, weather and stock services) which send data uni-directionally to multiple users.
It is desirable that existing mobile stations have the capability to support such services. As indicated above, existing mobile stations commonly include standardized modems which allow for data transfer via circuit-switched connections.
Many existing mobile stations fail to provide the capability to support GPRS. In order to instantly adapt a portable computer of an existing mobile station for such support requires enhancements be made to the operating system of the portable computer which would be not only time consuming, but also expensive.