British Telecommunications Public Limited Company

Mohammad Zoualfaghari

Ruth Brown

Joshua Daniel

Gery M Ducatel

Ian Neild

Hamid Gharib

Michael A Fisher

Richard Gedge

Gery Ducatel

Paul Anthony Putland

Tim Stevens

Michael Williamson

Paul Putland

Michael Fisher

A passive sensor for detecting the operation of a light source includes a photosensor which, when illuminated by the light source, delivers a voltage to a field effect transistor (FET) which can switch a circuit to control a device at a remote location. The FET transitions rapidly between very low resistance (short circuit) and very high resistance (open circuit), allowing a binary indication to be given in the circuit. The circuit can be used to charge an electrical storage device to allow later download of recent status of the lamp by detecting the charge stored in the device.

Passive optical sensors

A computer implemented method for code distribution by a base station to a target device via a network, the distribution being made via one or more distribution servers arranged between the base station and the target device on the network, is disclosed.

Untrusted code distribution

A spread spectrum system is used for transmitting data to devices in a distributed system. Each device has a respective spread spectrum code, and has a corresponding encoder in a central control system operating the same spread spectrum codes, the encoded data relating to the devices being aggregated over a shared channel. An additional broadcast spread spectrum coding sequence is allocated to a broadcast channel readable by a plurality of the devices using a command extraction function and used to transmit general commands for operation by the plurality of devices. Individual actuators may be arranged to respond in different ways to such a broadcast command, for example switching some on and switching others off. The broadcast may also be used to change the coding sequences allocated to individual devices, allowing flexible use of the available spread-spectrum coding sequences.

Broadcasting in a communications network

A spread spectrum system is used for transmitting data to and from devices operable as sensors and actuators in a distributed system. Communication is made through a series of aggregation nodes in a branched hierarchical network. Each device and aggregation node has a respective spread spectrum code, and has a corresponding encoder/decoder in a central control system operating the same spread spectrum codes, the encoded data relating to the devices being aggregated over a shared channel. At each level in the hierarchy the aggregated signals to/from the next level are recoded. This allows the same codes to be re-used at different levels, and in different sub-branches in the same level, increasing the number of devices that can be served on one channel.

Branched communications network

Methods and systems are disclosed for enabling sensor data to be collected from sensor devices (), the sensor devices being configured to sense a condition and to send sensor messages according to a wireless communication protocol to a wireless access point () of a local network (), the sensor messages comprising sensor data indicative of said condition, said sensor messages also comprising a destination indication indicative of a predetermined network location outside the local network ().

Collection of sensor data from sensor devices

A fixed communication network is disclosed in which a plurality of transmitters feed signals via tributary transmission lines of different lengths onto a shared network component. A timing reference signal is distributed to the transmitters. The shared network component in some embodiments takes the form of a transmission line. In order to enable the sharing of the capacity of the shared network component, each of the plurality of transmitters codes data for transmission in accordance with a code division multiple access scheme. The efficiency of usage of the shared network component is improved by synchronizing the arrival of the encoded bits at the shared network component. This is achieved by populating a store within each transmitter with a pre-set timing offset, and timing the transmission of data in accordance with the timing reference signal received by the transmitters and the pre-set timing offset.

Communications network

Disclosed herein is a computer implemented method for receiving code distributed by a base station at a target device via a network, the distribution being made to one or more destination devices including the target device via one or more distribution servers arranged between the base station and the one or more devices on the network, wherein the base station maintains a first blockchain data structure storing one or more blocks and having a state determined by a most recently committed block in the first blockchain.

Blockchain state reliability determination

An optical network is disclosed which includes an optical fiber shared by a plurality of transmitters using code division multiple access techniques. The transmitters are connected by tributary optical fibers to the shared optical fiber. In code division multiple access techniques, each communication is encoded with a distinctive code which enables a receiver to extract the communication intended for it from amongst communications intended for other receivers. It is found that synchronizing the communications on the optical fiber improves the ability of a receiver to extract the communication intended for it. Injecting an optical pulse signal into the optical network, and using the tributary optical fibers to carry the clock signal to the transmitters provides an inexpensive method of synchronizing the transmitters which feed signals onto the optical fiber. The technology is of use in optical networks, and other transmission line networks, and is well-suited to use in local area networks.

Growing community of inventors

London, United Kingdom

Mohammad Zoualfaghari