Wireless personal local area network

#computer terminals and peripheral devices are now used in practically every aspect of life. Computer terminals come in all shapes and sizes and vary greatly in terms of function, power and speed. Additionally, the number of peripheral devices which can be attached to the computer terminals is increasing. Many peripheral devices exist such as printers, modems, graphics scanners, text scanners, code readers, magnetic card readers, external monitors, voice command interfaces, external storage devices, and so on.

#Computer terminals and peripherals have become dramatically smaller and more portable. Personal computers and peripherals are small enough to sit on the desk at work. Smaller still are lap top computers and notebook computers. There are computer terminals which are small enough to be mounted in a vehicle such as a delivery truck or on a fork lift. Still smaller are the hand held terminals typically used for their portability features where the user can carry the computer terminal in one hand and operate it with the other.

#Despite the reduction in computer size, the computer terminal still must physically interface with the peripheral devices. Thus, there must either be a cable running from one of the computer terminal to each device or the computer terminal must be docked with the device while the information transfer is to take place.

#FIG. 1a illustrates a warehouse environment incorporating a communication network which maintains communication connectivity between the various network devices according to the present invention.

#FIG. 1b illustrates other features of the present invention in the use of a mobile vehicle and an associated microLAN network which is capable of detaching from the main communication network when moving out of range of the main network to perform a service, and reattaching to the main network when moving within range to automatically report on the services rendered.

#FIG. 2 is a diagrammatic illustration of the use of a microLAN supporting roaming data collection by an operator according to the present invention.

#FIG. 1a illustrates a warehouse environment incorporating a communication network which maintains communication connectivity between the various network devices according to the present invention. Specifically, a worker utilizes a computer terminal 7 and a code reader 9 to collect data such as identifying numbers or codes on warehoused goods, such as the box 10. As the numbers and codes are collected, they are forwarded through the network to a host computer 11 for storage and cross-referencing. In addition, the host computer 11 may, for example, forward cross-referenced information relating to the collected numbers or codes back through the network for display on the terminal 7 or for printing on a printer 13. Similarly, the collected may be printed from the computer terminal 7 directly to the printer 13. Other exemplary communication pathways supported by the present invention include messages exchanged between the computer terminal 7 and other computer terminals (not shown) or the host computer 11.

#Many of the devices found in the illustrative network are battery powered and therefore must conservatively utilize their radio transceivers. For example, the hand-held computer terminal 7 receives its power from either an enclosed battery or a forklift battery (not shown) via a docking station within the forklift 14. Similarly, the code reader 9 operates on portable battery power as may the printer 13. The arrangement of the communication network, communication protocols used, and data rate and power level adjustments help to optimize battery conservation without substantially degrading network performance.

#The overall communication network of the present invention is arranged into two functional groups: 1) a main communication network; and 2) a microLAN network. The main communication network in the illustrated warehouse embodiment includes a hard-wired backbone LAN 19 and base stations 15 and 17. A host computer 11 and any other non-mobile network device located in the vicinity of the backbone LAN 19 can be directly attached to the backbone LAN 19. However, mobile devices and remotely located devices must maintain connectivity to the backbone LAN 19 through either a single base station such as the base station 15, or through a multi-hop network of base stations such as is illustrated by the base stations 15 and 17. The base stations 15 and 17 contain a higher power transmitter, and provide coverage over the entire warehouse floor. Although a single base station may be sufficient, if the warehouse is too large or contains interfering physical barriers, the multi-hop plurality of base stations 17 may be necessary. Otherwise, the backbone LAN 19 must be extended to connect all of the base stations 17 directly to provide sufficient radio coverage. Through the main communication network, relatively stable, long range wireless and hard-wired communication is maintained.