Cellular wireless internet access system using spread spectrum and internet protocol
View Patent ↗A cellular wireless internet access system which operates in the 2.5 to 2.68 GHz band and which must comply with complex government regulations on power levels, subscriber equipment and interference levels yet which provides high data rates to users and cell sizes of 1½ miles radius or more from base stations with subscriber equipment and antennas mounted indoors. Such base stations are mounted low and use spread-spectrum transmission to comply with interference rules with respect to adjacent license areas. An unidirectional tear-drop coverage pattern is used at multiple cells to further reduce interference when required. Time division duplex is used to allow the system to operate on any single channel of varying bandwidth within the 2.5 to 2.68 GHz band. Backhaul transmission from base stations to the Internet is provided using base station radio equipment, operating either on a different frequency in the band or on the same frequency using a time-division peer-to-peer technique. Different effective data-rates are provided by a prioritization tiering technique.
1. A cellular wireless internet access system comprising:
a plurality of portable subscriber terminals each having a directly attached antenna for communicating in a predetermined frequency band with a predetermined nearby cellular base station;
a plurality of cellular base stations each transmitting and receiving in said predetermined frequency band at a single frequency with a predetermined said plurality of said subscriber terminals; and
means for operating said base station on a small frequency allocation obtainable anywhere within the designated frequency band using a single frequency channel of varying bandwidth between 6 and 24 MHz using different spread spectrum transmission chip rates; and
means for operating said base station in a time-division-duplex mode to enable said transmitting and receiving at said single frequency channel thus avoiding the need for separate channels spaced apart for transmit and receive and including means for allocating the ratio of time for transmitting and receiving on a predetermined basis said time division as a function of expected traffic demand;
means for providing high net data rates of 1.5-3.0 Mbps using a plurality of data bearer subchannels on said single frequency channel, orthogonal downlink spreading codes for CDMA transmission, and successive interference cancellation or simultaneous uplink spreading codes.
2. A system as in claim 1 where each band is divided in the time domain into frames and each frame has a predetermined number of time slots allocated to control, uplink, and downlink communications between said cellular base stations and subscriber terminals.
3. A system as in claim 2 where some of said frames are dedicated to backhaul communication between base stations on a peer-to-peer basis.
4. A system as in claim 2 where the data transmission rate is increased during time domain frames used for backhaul communication by switching to directional antennas during these timeslots thus providing an improved radio channel quality to support such increased data rate.
5. A system as in claim 1 where said means for using different transmission chip rates provides net data rates of 1.5-3.0 Mbps on said small frequency allocation.