Aironet Wireless Communications, Inc.

Cisco Systems Inc.

Telxon Corporation

Symbol Technologies, LLC

Teletransactions, Inc.

Michael L Trompower

Nainesh P Shah

Paul F Struhsaker

Andrew J Spry

Douglas A Smith

Daniel J Morelli

Philip H Belanger

Marvin L Sojka

Victor K Paulsen

James K Holt

George L Grim, Iii

A system and method is provided for adjusting transmission power of different portions of a data packet. The system and method is especially useful when utilizing the IEEE 802.11 standard protocol due to the varying transmission data rates of a packet. A IEEE 802.11 packet includes a preamble portion, a header portion and a data portion. The preamble portion has a data rate of 1 Mbps, the header has a data rate of 1 or 2 Mbps and the data portion has a data rate of 1, 2, 5.5 or 11 Mbps. At a given fixed power level, a transmission at a higher data rate has a lower transmission range than a transmission at a lower data rate. Therefore, the present invention provides for a system and method that adjusts the power level of different portions of a data packet, so that the entire data packet has a more uniform range. This eliminates the need for components in the system receiving a preamble portion of a transmission at higher ranges to remain idle during transmission of an entire frame. The system and method can be applied to both access points and mobile units in a cellular communications system.

802.11 networks using dynamic power control for RF transmission

A transceiver which keeps circuitry associated with a receiver in a powered down state during periods when a Received Signal Strength Indicator (RSSI) indicates that a signal being received is below a pre-determined threshold level, and which begins to power up the transmitter as soon as it is determined that a packet being received requires a response. The RSSI signal represents the strength of any signal current being received, and if the RSSI signal falls below a given threshold level, digital circuitry associated with the back-end circuitry of the receiver system is disabled. If the RSSI signal rises above the threshold level, the digital circuitry of the receiver is enabled. A control circuit within the transceiver processes the packet as it is received to determine whether the packet requires a response. If it is determined that a response is necessary, the control circuit provides a control signal to the transmitter to power up the transmitter from a sleep mode even before the entire packet has been received and processed. The control circuit then continues to process the remainder of the packet as it is received while the transmitter powers up from the sleep mode. In this manner, the transmitter will become stabilized much earlier. Accordingly, the transceiver is able to respond more quickly than conventional devices and is thus able to increase response times and overall data exchange rates. Moreover, battery power of the transceiver is utilized more efficiently compared to devices which must continuously maintain the receiver and transmitter in fully powered modes.

Transceiver control with sleep mode operation

A pager system which enables users to avoid having to pay monthly service charges. The pager system is particularly useful in that it can be coupled easily to an existing local area network (LAN) to provide paging capabilities within a local area (i.e., a campus) such as a building or set of buildings. Thus, businesses, universities, etc., who currently have a LAN or contemplate installing one can couple the pager system to the LAN in order to provide localized paging. Such localized paging is provided without the need to pay monthly service charges to paging service providers. A business, university, etc., incurs primarily only an initial cost to purchase the pager equipment. Therefore, the present system represents a substantial cost savings compared to WAN based paging service providers for those desiring localized paging.

Campus area pager system

A wireless communication device and method which includes the introduction of a auxiliary receiver or transceiver which is included in a base station or mobile terminal in addition to a transceiver used to communicate between devices. The auxiliary receiver or transceiver serves to monitor substantially continuously the noise conditions on available communication channels other than the channel currently being utilized for communication between devices. Whenever the noise conditions on the current channel goes above a preset threshold level, for example, the base station or mobile terminal is informed by virtue of the operation of the auxiliary receiver or transceiver of the best alternative channel to which to change.

Wireless communication method and device with auxiliary receiver for selecting different channels

A cellular communication system hand-off protocol which helps minimize down time associated with a mobile device roaming among different cells in which different cells employ different communication channels (e.g., different frequency hopping sequences). In a preferred embodiment, each base station is configured to communicate its own particular hopping sequence to the host computer via the system backbone. Each base station then provides to mobile devices which are registered thereto information regarding the particular hopping sequences employed by other base stations servicing cells into which the mobile device may roam. Such information includes the particular hopping sequences together with an indication of what location in the sequence the base stations are currently at in any given time. In addition, such information may include an indication of the intervals at which a base station is configured to transmit a beacon packet (for passive scanning operation), or at what intervals test pattern packets are transmitted to allow for signal quality evaluation.

Cellular system hand-off protocol

A cellular communication system in which dedicated repeater controller transceivers are included in base stations and wireless base stations. The repeater controller transceivers are configured to operate on a different channel as compared to communications received by or transmitted directly from mobile terminals. By utilizing a dedicated channel for communications between the base stations and wireless base stations, the contention areas formed by overlapping cell areas is effectively eliminated. The different channels may be based on differences in parameters such as frequency and/or data encoding techniques.

Cellular communication system with dedicated repeater channels

A cellular communication system in which dedicated repeater controller transceivers are included in base stations and wireless base stations. The repeater controller transceivers are configured to operate on a different channel as compared to communications received by or transmitted directly from mobile terminals. By utilizing a dedicated channel for communications between the base stations and wireless base stations, the contention areas formed by overlapping cell areas is effectively eliminated. The different channels may be based on differences in parameters using infrared communication techniques.

A cellular communication system hand-off protocol which helps minimize down time associated with a mobile device roaming among different cells in which different cells employ different communication channels (e.g., different frequency hopping sequences). In a preferred embodiment, each base station is configured to communicate its own particular hopping sequence to all other base stations via the system backbone. Each base station then provides to mobile devices which are registered thereto information regarding the particular hopping sequences employed by other base stations servicing cells into which the mobile device may roam. Such information includes the particular hopping sequences together with an indication of what location in the sequence the base stations are currently at in any given time. In addition, such information may include an indication of the intervals at which a base station is configured to transmit a beacon packet (for passive scanning operation), or at what intervals test pattern packets are transmitted to allow for signal quality evaluation.

An apparatus and process for improving the performance of a cellular communication system using direct sequence spread spectrum techniques is disclosed. The apparatus and process enable dynamic modification of communication system parameters including PN code length, chipping rate and modulation technique for transmission of a data packet. Modification is based on proximity of the transmitter and receiver, noise level, transmitter and receiver capabilities and other factors. The system makes tradeoffs between data transmission speed and communication range to improve system performance.

Cellular communication system with dynamically modified data

A wireless communication device and method which includes the introduction of a auxiliary receiver or transceiver which is included in a base station or mobile terminal in addition to a transceiver used to communicate between devices. The auxiliary receiver or transceiver serves to monitor conditions on available communication channels other than the channel currently being utilized for communication between devices.

Wireless communication method and device with auxiliary receiver for

A direct sequence spread spectrum (DSSS) system which uses PN sequences to encode data so as to increase data throughput. In particular, a system for communicating a plurality of data values using multiple spreading sequences is provided. The system transmits data by selecting at least one of the multiple spreading sequences based on at least one data value included in the plurality of data values; and transmitting other data values included in the plurality of data values using the at least one of the multiple spreading sequences to spread the other data values.

Direct sequence network and method using PN sequence selection to

A network cellular communication system with power based locator system in which the location of a mobile communication unit within the network can be determined approximately. In particular, the power based locator system includes a pre-stored map of locations of a plurality of base stations within the network and the respective network cell coverage areas for those base stations. Each of the plurality of base stations is able to change the size of its respective cell by varying transmitter and receiver power levels. By incrementally changing its respective cell coverage area, the base station can effectively narrow down the region in which a mobile communication unit is located. The region information is correlated with the pre-stored map of locations to determine approximately where in the cellular communication network the mobile communication unit is located. Additionally, the present invention affords for substantially continuous connectivity of most or all mobile communication units to the network backbone, even when one of the plurality of base stations reduces the size and/or shape of its respective cell in order to locate a mobile communication unit.

Power based locator system

An apparatus and process for improving the performance of a cellular communication system using direct sequence spread spectrum techniques. The apparatus and process enable dynamic modification of communication system parameters including PN code length, chipping rate and modulation technique for transmission of a data packet. Modification is based on proximity of the transmitter and receiver, transmitter and receiver capabilities and other factors. The system evaluates tradeoffs between data transmission speed and communication range to improve system performance.

A network cellular communication system with power based locator system in which the location of a mobile communication unit within the network can be determined approximately. In particular, the power based locator system includes a pre-stored map of locations of a plurality of base stations within the network and the respective network cell coverage areas for those base stations. Each of the plurality of base stations is able to change the size of its respective cell by varying transmitter and receiver power levels. By incrementally changing its respective cell coverage area, the base station can effectively narrow down the region in which a mobile communication unit is located. The region information is correlated with the pre-stored map of locations to determine approximately where in the cellular communication network the mobile communication unit is located.

Growing community of inventors

Navarre, OH, United States of America

Michael L Trompower