Abstract: A method of connecting devices to a network is provided. The method includes providing base stations connected to a network, and at each of the base stations, receiving probe signals from terminal devices. For each of the terminal devices, the base station calculates a signature waveform based on a time-reversed waveform of a channel response signal derived from the corresponding probe signal. For each of the terminal devices, the base station determines a downlink transmit signal for the terminal device based on the downlink data and the corresponding signature waveform, and transmits the downlink signals to the terminal devices. Several base stations have overlapping broadcast regions, several terminal devices are located within the overlapped broadcast regions, the base stations transmit the downlink signals using a same frequency band, and some downlink signals transmitted by base stations having overlapping broadcast regions also overlap in time.

Abstract: A handshaking process for time-reversal wireless communication is provided. A first device receives a handshake signal transmitted from a second device through multiple propagation paths, the handshake signal including a preamble and a training sequence, in which the training sequence includes a sequence of symbols known to the first and second devices. A synchronization index is determined based on the preamble, and the training sequence in the handshake signal is identified based on the synchronization index. A channel response signal is determined based on the received training sequence, and a signature waveform that is a time-reversed signal of the channel response signal is generated. A transmission signal is generated based on transmit data and the signature waveform, in which the transmit data are data configured to be transmitted to the second device.

Abstract: In an asymmetric time-reversal wireless system, a base station includes an input circuit configured to, during a hand-shake period, receive a channel response signal derived from a probe signal sent from a first terminal device to the apparatus through multiple wireless propagation paths, and during an uplink transmission period, receive combined signals that include a signal from the first terminal device and a signal from a second terminal device. The base station includes a data processor configured to calculate a signature waveform for the first terminal device based on the channel response, and determine the signal sent from the first terminal device during the uplink transmission period based on the combined signals and the signature waveform for the first terminal device.

Abstract: In a time-reversal wireless system, a transceiver receives a combined signal that includes signals from a plurality of devices, each device sending a signal to the transceiver through multiple wireless propagation paths. Signals sent from each of the devices are estimated based on the combined signal and a signature waveform associated with the device. Interference associated with the estimated signal from each of the devices is determined based on the estimated signals from the devices. The signal sent from each of the devices is determined by subtracting the interference associated with the estimated signal associated with the device from the estimated signal associated with the device.

Abstract: A shield and a method for shielding are provided for preventing radio frequency energy from entering or exiting an electronic device. The shield includes a frame surrounding the electronic device. The frame has a first frame wall and a second frame wall arranged with a first gap in between that extends along the first frame wall. The first frame wall is arranged in a first plane, the second frame wall is arranged in a second plane, and the first plane intersects the second plane. The shield also includes a cover surrounding the frame. The cover has a first cover wall and a second cover wall arranged with a second gap in between that extends along the second cover wall. The arrangements of the first gap and the second gap prevent radio frequency energy from entering or escaping the electronic device.

Abstract: A wireless personal mobile terminal in a cellular data network includes a packet radio transceiver for communicating with cellular base stations and a paging receiver for receiving paging signals from a paging transmitter serving a large geographical area. The wireless personal mobile message unit has power-saving features built into the signal format. This personal mobile message unit accommodates many communication applications due to the high bandwidth and the low latency achieved in the cellular data network. Low-power operation and wide coverage is achieved using existing one-way paging infrastructure. The wireless personal mobile unit can be achieved inexpensively by modifying a conventional one-way pager.

Abstract: A system for creating a computer database model of either measured data network throughput properties or wireless communication signal properties within a facility by measuring the desired properties at a plurality of locations within the facility and embedding the measured properties at the location of measurement represented in a three-dimensional facility drawing database.

Abstract: A time slot synchronizer that includes a sampler, which is configured to successively sample a baseband signal. The baseband signal is divided into a number of frames, and each frame is divided into a plurality of symbols. The sampler divides each symbol into a plurality of sample bins and generates a first sample group from a first frame by sampling each symbol in the first frame. The sampler uses a predetermined first and second sample bin for sampling the first frame. Next, the sampler generates a second sample group from a second frame by sampling each symbol in the second frame in a third and fourth sample bin. The third and fourth sample bins, however, are shifted a certain number of sample bins relative to the first and second sample bins, respectively.

Abstract: A predetermined error vector magnitude reduction circuit exploits scatter patterns that develop at the output of modem wireless communication systems during phase state transition. Digital inphase and quadrature input signals to the circuit, typically from a baseband processor, are compared to known characteristic bit patterns that are pre-stored in a lookup table. Modified data that correspond to the known characteristic bit patterns is supplied to the circuit to replace the data signals themselves. The modified data may be digital data that replaces the digital signals at the input to the inphase and quadrature DACs, or analog data that replaces the analog output of the DACs.

Abstract: Synchronized receiver circuitry and methods are provided for a spread-spectrum communications system which includes a transmitter for generating a data-modulated carrier signal encoded with a predetermined discrete-stepped, cyclical pseudo-random noise code sequence, and a receiver for despreading and demodulating the encoded spread-spectrum modulated carrier signal. The receiver has a pseudo-random noise code generator, a mixer connected to the pseudo-random noise code generator for mixing the encoded spread-spectrum modulated carrier signal with the code sequence provided by the pseudo/random noise code generator to despread the carrier signal, and an indicator in the receiver for generating a received signal strength indicator analog signal. The synchronized receiver includes a clock which provides a frequency output corresponding to the frequency of the clock driving the pseudo-random noise code generator in the transmitter.

Abstract: A display for a mobile radio telephone apparatus includes a single 7, 8 segment LED display for displaying alphanumeric characters one at a time in sequence as dialed, and which also displays indications of various operating parameters of the telephone apparatus, such as a roaming function or in use status, by using predetermined ones of the same segments that are used to display the alphanumeric characters. In this way, a single seven segment display plus an eighth display indicator segment is all that is required to display any character, digit or indication of operational status of the mobile radio telephone apparatus.

Abstract: 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.

Abstract: 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.

Abstract: A network communication system in which access points providing wireless access to the system reroute misrouted information packets in the event the location of a mobile unit has changed. Regardless of whether a host computer or other network device is capable of updating in its position table the changing locations of the mobile units, information packets directed to the mobile units from the host computer or other network device are still properly delivered.

Abstract: 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.

Abstract: A cellular communication device for a cellular communication network which includes a radio-frequency (RF) transmitter for transmitting an RF signal at an output power level to one or more other devices in the cellular communication network; an RF receiver for receiving an RF signal from one or more other devices in the cellular communication network; and a gain control circuit for sampling the output power level to obtain a sampled output power level signal, digitizing the sampled output power level signal, and adjusting a gain of the RF transmitter based on the digitized sampled output power level signal in order that the output power level of the RF transmitter approaches a predefined output power level. The gain may also be adjusted in response to the Received Signal Strength Indicator (RSSI) in order to conserve battery power.

Abstract: 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.

Abstract: 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.

Abstract: A peripheral device for a computer, including a first portion including electronic circuitry and a light source for emitting light; a second portion selectively detachable from the first portion, the second portion including a light transfer medium for directing light from one end of the light transfer medium to another end; and wherein the one end of the light transfer medium is optically aligned with the light source when the second portion is attached to the first portion, and the light transfer medium directs at least a fraction of the light emitted from the light source from the one end to the another end for display from the second portion.

Abstract: The present invention relates to a peripheral apparatus which enables users to communicate with a mobile device via radio as well as optical transmission substantially simultaneously. The peripheral apparatus includes a radio card which includes circuitry for conducting RF communication; and an antenna apparatus that is selectively detachable from the radio card, the antenna apparatus includes an optical device for conducting optical communications. When the antenna apparatus is attached to the radio card, the radio card is capable of radio and optical communications. The peripheral apparatus is particularly useful in that an available com port does not have to be solely dedicated for optical communications. Furthermore, the peripheral apparatus avoids the problems associated with employing external wires to connect an optical transceiver to the mobile device.