A hierarchical communication
system is described in which two
wireless local area networks exhibiting substantially different characteristics are employed to link inherently portable or mobile computer devices. A series of radio base stations make up a
infrastructure network. The
infrastructure network and at least one
portable computer device make up the first
local area network. The communication on the first
local area network is accomplished by
spread spectrum frequency hopping communication A second
local area network allows for radio communication between a
portable computer device and
peripheral devices with built-in transceivers utilized by the
portable computer device. The communication in each local
area network is controlled by a reservation access communication protocol. The communication protocol facilitates frequency hopping synchronization and supports adaptive
data rate selection based upon the quality of communication on the
communication channel. The communication protocol prevents interference between communication on the first local
area network and communication on the second local
area network. In a premises LAN, a series of radio base stations and a backbone LAN make up an
infrastructure network. The infrastructure network and at least one
mobile computing device make up a higher-power LAN, utilizing a frequency hopping protocol. A lower-power LAN allows for radio communication between a
mobile computing device and -
peripheral devices, utilizing a single-frequency
spread spectrum protocol. A vehicular LAN provides for short-range communication between a vehicle terminal and a portable terminal. When out of direct RF range of the premises LAN, the vehicle terminal maintains indirect communication when necessary with the premises LAN via one of several alternate RF channels. A
microprocessor, located inside radio units which participate in multiple LAN's, selects the appropriate protocol,
frequency band and
power level for communicating through the network.