The present invention is generally directed to a system for monitoring a variety of environmental and/or other conditions within a defined remotely located region. In one aspect, a system is configured to monitor utility meters (613) in a defined area. The system is implemented by using a plurality of wireless transmitters (614), each integrated into a sensor (612) adapted to monitor a particular data input. The system also includes a plurality of transceivers (221) that are dispersed throughout the region at defined locations. The system uses a local gateway (210) to translate and transfer information from the transmitters to a dedicated computer (260) on a network (230). The dedicated computer collects, compiles and stores the data for retrieval upon client demand across the network. The computer further includes means for evaluating the received information and identifying an appropriate control signal to be applied at a designated actuator.

System and method for monitoring and controlling remote devices

A location reporting paging communication system comprising space satellites, ground stations and a remote receiving unit adapted to resolve a global position from signals transmitted from a communication transmitter. The subscriber in possession of the remote receiving unit updates the paging network with global positioning information. A caller paging a subscriber in possession of the remote receiving unit may request the global location of the remote receiving unit. The paging network could divulge or block such information from a caller depending on the requirements of the subscriber.

Location reporting satellite paging system with optional blocking of location reporting

A packet-based, hierarchical communication system, arranged in a spanning tree configuration, is described in which wired and wireless communication networks exhibiting substantially different characteristics are employed in an overall scheme to link portable or mobile computing devices. The network accommodates real time voice transmission both through dedicated, scheduled bandwidth and through a packet-based routing within the confines and constraints of a data network. Conversion and call processing circuitry is also disclosed which enables access devices and personal computers to adapt voice information between analog voice stream and digital voice packet formats as proves necessary. Routing pathways include wireless spanning tree networks, wide area networks, telephone switching networks, internet, etc., in a manner virtually transparent to the user. A voice session and associate call setup simulates that of conventional telephone switching network, providing well-understood functionality common to any mobile, remote or stationary terminal, phone, computer, etc.

Hierarchical Data Collection Network Supporting Packetized Voice Communications Among Wireless Terminals and Telephones

A seamless solution transparently addresses the characteristics of nomadic systems, and enables existing network applications to run reliably in mobile environments. The solution extends the enterprise network, letting network managers provide mobile users with easy access to the same applications as stationary users without sacrificing reliability or centralized management. The solution combines advantages of existing wire-line network standards with emerging mobile standards to create a solution that works with existing network applications. A Mobility Management Server coupled to the mobile network maintains the state of each of any number of Mobile End Systems and handles the complex session management required to maintain persistent connections to the network and to other peer processes. If a Mobile End System becomes unreachable, suspends, or changes network address (e.g., due to roaming from one network interconnect to another), the Mobility Management Server maintains the connection to the associated peer task—allowing the Mobile End System to maintain a continuous connection even though it may temporarily lose contact with its network medium. In one example, Mobility Management Server communicates with Mobile End Systems using Remote Procedure Call and Internet Mobility Protocols.

Method and apparatus for providing mobile and other intermittent connectivity in a computing environment

A multilaterating two-way message delivery system for mobile resource management provides efficient two-way radio data communication for multitudes of portable transponders (22) using a single frequency in half-duplex communication. The system includes at least one transponder device (22) which transmits and receives data using a radio frequency communication link, and an array of at least three bases (12a-f) which communicate with the transponder device (22) using the radio frequency communication link. The radio frequency communication link employed by each base station (12a-f) and the transponder device (22) is designed to provide multilateration information and to deliver message data simultaneously. Further, a control arrangement (10) is coupled to the array of base stations to coordinate the communication between the base stations (12a-f) and the transponder devices (22). Time division multiplex and spread spectrum technology is employed by the system for communication efficiency and minimizing the effect of multipath interference.

Communication system and method for determining the location of a transponder unit

A technique for spread-spectrum communication which uses more than one mode and more than one frequency band. Selectable modes include narrowband mode and spread-spectrum mode, or cellular mode and microcellular mode. Selectable frequency bands include both licensed and unlicensed frequency bands, particularly frequency bands including the 902-928 MHz, 1850-1990 MHz, and 2.4-2.4835 GHz frequency bands. Spread-spectrum communication channels are 10 MHz or less in width. The frequency band onto which spread-spectrum signals are encoded may be changed upon a change in environment or other control trigger, such as establishment or de-establishment of communication with a private access network. A multi-band transmitter comprises a single frequency synthesizer and a frequency source (e.g., a local oscillator), coupled to a selectable band pass filter. A multi-band receiver capable of monitoring one or more frequency bands comprises bank of bandpass filters and a demodulator comprising a single frequency synthesizer and a frequency source.

Multi-band, multi-mode spread-spectrum communication system

An integrated communication system supporting multiple TDMA or TDD communication protocols, and includes means for selectively communicating according to either protocol. Each protocol defines time frames and/or time slots of a different duration (901, 911), from which is derived a composite time frame (925) having a predefined timing structure. A first base station unit (104) communicates in a first set of time slots of the composite time frame according to a first TDMA or TDD protocol, and a second base station unit (104) (which may be collocated with the first base station unit) communicates in a second set of time slots of the composite time frame according to a second TDMA or TDD protocol. Coordinating electronics (such as a GPS receiver in one or both base station units) are provided so as to prevent collisions between communications occurring between each base station unit and its respective users. In a particular embodiment, a first protocol is GSM protocol, and a second protocol is a TDD protocol utilizing spread spectrum techniques. The TDD protocol is structured so that each time slot is twice the duration of a GSM time slot, and each time frame is four times the duration of a GSM time frame. The system may comprise a number of 'stacked' base stations in a single cell, each operating over a different frequency or using different spreading codes.

Coexisting communication systems

A dual-mode transmitter having an antenna (109), a mode controller (103), a source encoder, a tunable-frequency synthesizer (105), a chip-code generator (107), a spread-spectrum modulator (111), a narrowband modulator (113), a power amplifier (115), and an adjustable bandpass filter (117). Also provided is a dual-mode receiver having a mode controller (103), a tunable-frequency synthesizer (105), a chip-code generator (107), an antenna (109), an adjustable bandpass filter (117), a preamplifier (205), a frequency converter (209), an IF amplifier (211), a spread-spectrum despreader (215), a spread-spectrum demodulator (217), a narrowband modulator (213), and a source decoder. For the transmitter and receiver, the mode controller (103) selects receiving a narrowband modulation or a spread-spectrum modulation. The tunable-frequency synthesizer (105) generates a local oscillator signal for the receiver, and a carrier signal for the transmitter. The chip-code generator (107) generates a chip code signal for both the transmitter and the receiver. With a narrowband modulation setting of the mode controller (103), the transmitter and receiver have the adjustable bandpass filters (117) adjusted to a narrowband width for telephone communications. With a spread-spectrum setting of the mode controller, the adjustable bandpass filters (117) and the system are adjusted to transmit and receive a wide bandwidth for passing the spread-spectrum signal.

Dual mode transmitter and receiver

An apparatus for decoding a received spread spectrum signal having a data signal modulated with a pseudo-noise code and transmitted as an RF spread spectrum signal. A first reference register holds a first pseudo-noise signal, a second reference register holds a second pseudo-noise signal, and a receive-register holds a received spread spectrum signal. A first modulo adder adds each chip of the received spread spectrum signal with each respective chip of the first pseudo-noise signal, thereby generating a first plurality of chip-comparison signals. A first summer adds the first plurality of chip-comparison signals, generating a first correlation signal. The comparator compares the correlation signal to an upper-threshold level and a lower-threshold level, and respectively generates a first data-symbol signal or a second data-symbol signal.

Spread spectrum correlator

An apparatus for decoding a spread spectrum signal coded with a pseudonoise code. A count control (30) is coupled to a clock generator (31) which is connected to a code generator (32) and reference registers (33). The code generator (32) is also connected to the reference registers (33). The count control (30) controls the length of the pseudonoise signal chosen by code selector (34) to be detected by the receiver, and sends signals to the code clock generator (31) to cause code generator (32) to output a code of length L to reference registers (33). Count control (30) triggers code clock generator (31), triggering code generator (32) and reference registers (33). The code selection circuit (34) outputs to the code generator (32). A single code may be loaded into the reference registers (33), or the reference registers (33) can be periodically loaded with different codes until a match occurs.

Robert C. Dixon

Papers

Multi-band, multi-mode spread-spectrum communication system

Coexisting communication systems

Dual mode transmitter and receiver

Spread spectrum correlator

Asymmetric spread spectrum correlator