Koninklijke Philips Corporation N.v.

U.S. Philips Corporation

David Hillary Evans

Dong Wang

Richard J Caldwell

Kevin Robert Boyle

Paul John Rankin

Robert Fifield

Ian M Clarke

Kenneth Holford

Bhavin S Khatri

Stuart M Feeney

Deborah L Raynes

A coordinator switching method and corresponding apparatus () are provided. One or more candidate coordinators () to replace a coordinator () of a medical body area network (MBAN) () are identified. The coordinator () is associated with one or more devices () of the MBAN (). One of the identified candidate coordinators () is selected as a destination coordinator. The destination coordinator () is requested to replace the coordinator () and allocate resources for the devices (). Acceptance of the request and data identifying the allocated resources for the devices () is received from the destination coordinator (). The devices () are instructed to associate with the destination coordinator () using the allocated resources.

Coordinator switching method for medical body area networks

A personal area network (PAN) coordinator () of a medical body area network (MBAN) () allocates multi-periodic guaranteed time slots (GTSs) to sensor devices () of the MBAN (). The PAN coordinator () includes a controller () configured to receive a request for a multi-periodic GTS from a sensor device () of the MBAN (). The request includes a period indicating a periodicity with which the multi-periodic GTS is requested. In response to the request, the controller () determines a GTS allocation including a starting frame and transmits a descriptor to the sensor device (). The descriptor includes information to identify the starting frame.

MAC enhancement to support multi-periodic GTS allocation for personal area network (PAN) systems

A wireless local area network (LAN) comprises an access point which transmits a beacon signal at 0 dBm. The detection threshold of the mobile unit is &#x2212;65 dBm and thus the mobile unit is detected when located within 10 meters of the access point.

System for locating a mobile unit

In a radio communication system comprising a plurality of stations () operating in a peer-to-peer mode, each station stores information relating to the transmission parameters of other stations. Such information may include the frequency offset and received signal strength of signals from the other stations. One station acts as central controller and allocates time slots for transmission from a first station () to a second station (). Before the first station () receives a signal from the second station () it makes initial adjustments to its receiver circuitry depending on the stored information about previous signals received from that station (). This simplifies the task of adjusting the receiver circuitry during the preamble of the signal transmitted by the second station ().

Radio communication system

Method of operating a wireless communication system

An antenna diversity system includes at least two antennas. Each antenna may be connected via a common connection point to a receiver by a respective switch which presents a low impedance connection between the antenna and receiver in the on state and a substantially reactive load to the antenna in the off state. Selection of appropriate impedances for the off state load enables the antennas to function as an array with a variety of beam patterns depending on the state of the switches. Cycling through a sequence of switch states steers the antenna beam providing improved resistance to fading and multipath effects. Alternatively, the antennas may be connected to a hybrid coupler, which enables two beam patterns to be available simultaneously for signal quality measurement and comparison.

Antenna diversity system

A transmitter for transmitting orthogonal signals comprises a power amplifier ( ) having a transfer characteristic in which gain is substantially independent of applied bias voltage. A digital signal for transmission is monitored by a level detector ( ) which determines the peak output power required from the power amplifier ( ). This information is used by a power supply controller ( ) to control the DC bias voltage applied to the power amplifier ( ) so that the applied voltage is reduced for low signal levels and increased for high signal levels, thereby increasing the efficiency with which supplied power is converted to radiated power. The applied voltage may be changed for each output symbol, or may be continuously adapted to track the peak envelope power. This method of controlling the amplifier ( ) may be used in conjunction with coding schemes for reducing the peak to mean power ratio.

Orthogonal signal transmitter

In a cell of a microwave cellular video distribution system, e.g a multichannel video distribution system operating at frequencies of around 29 GHz or 40 GHz, the transmitting antenna is composed of individual antenna sectors (62a,62b,62c . . . ) for transmitting the microwave signal towards different sectors (216a,216b,216c . . . ) of the cell. In accordance with the present invention, a respective monitor (D,R) is present in each of the different sectors (216a,216b,216c . . . ) of each/the cell to monitor the microwave signal transmitted in that sector. The antenna sectors (62a,62b,62c . . . ) are individually fed through controllable feed means (59,60,61) which permit individual control of the power level of the microwave signals transmitted by the individual antenna sectors (62a,62b,62c . . . ), including the switching off of that sector. A feedback coupling (40,44,49) is present between each monitor (R,D) and the controllable feed means (59,60,61) of the respective antenna sector (62a,62b,62c . . . ) to control individually the power levels transmitted towards the different sectors (216a,216b,216c . . . ) of each cell. In this manner the transmission pattern in each cell can be controlled and adapted to improve the quality of signal reception as requested by subscribers (R), to increase the operational life of the transmitter(s) by minimizing transmitter power, and to enhance responsiveness to other desirable and/or acceptable demands placed on the signal transmission.

Microwave video distribution system and adaptable microwave transmitter

A printed antenna comprises an end fed elongate first dipole element (12) provided on one side of a dielectric substate (10). A second dipole element (16, 17) is provided on the opposite side of the dielectric substrate. The second dipole comprises first and second elongate elements (16, 17) disposed one on each side of the longitudinal axis of the first dipole element as viewed through the substrate. A ground plane (14) on the second side of the substrate is connected to the first and second elements (16, 17) at a distance from a free end of the first dipole element corresponding substantially to a quarter wavelength of the frequency (or centre frequency) above interest. The first and second elements (16, 17) are a quarter of a wavelength long and may be inclined relative to the first dipole element (12) or extend parallel thereto (4 (not shown)). Pairs of the printed antennas may be connected with switching elements to form antenna diversity arrangements.

Printed antenna

In addition to a first opening (11) forming a primary output from a waveguide cavity (10) of a microwave oscillator, a coupling aperture (12) in a reflective wall (32) provides a secondary output which does not degrade the performance or tuning characteristics of the source. Less than -20 dB of the source power may be coupled out via the aperture (12) and is used in a feed-back loop (12,21,23,24,36) with an harmonic mixer (21) and frequency discriminator (24) to stabilize the source. The mixer comprises a further waveguide section (15) separated from the source cavity (10) by the reflective wall (32). An advantageous mixer assembly comprises a circuit substrate which is mounted across the further waveguide cavity (15) and which carries an inductive probe by which the signal from the coupling aperture (12) is fed to an antiparallel pair of mixer diodes on the substrate. The whole assembly may be bolted together through holes (34).

Microwave oscillators and transmitters with frequency stabilization

A simple self-oscillating mixer circuit is provided, suitable for forming with an antenna (21) the complete front end of an inexpensive short-range FMCW radar. A modulating signal (40), e.g. from a sweep generator (44), is applied to a control terminal (14) to sweep the RF output (R) of the self-oscillating mixer SOM (10). A cancellation circuit (6 to 9) is connected between the control terminal (14) and an IF output line (13) to remove a corresponding modulation (41) which occurs on the IF line (13) and so to generate a substantially demodulated IF output signal (I). Advantageously a grounded-source MESFET in a feed-back network forms the SOM (10) and has the IF output line (13) taken from its gate. In this case the IF modulation (41) is inverted with respect to the modulating signal (40), and so the cancellation is achieved by adding the modulating signal (40) to the modulated IF output signal (41), e.g. via a resistor network 6 to 8.

Self-oscillating mixer circuits, and FMCW radar

In a waveguide oscillator, a Gunn diode or other negative-resistance oscillator device (2) has a resonant cap (3) for coupling to the waveguide (1), and a tuning varactor diode (11) is coupled by a probe (13) to the electromagnetic filed in the vicinity of the cap (3). In accordance with the invention, a mechanically simple, compact and cheap oscillator arrangement is obtained by integrating both the varactor diode (11) and the probe (13) in a circuit body (10) mounted in the waveguide (1), preferably in an area below the plane of the cap (3) so as to reduce perturbation of the filed. The probe is formed as a conductive track (13) on the circuit body (10), for example as a transmission line coupling to the electric field and preferably located at the front surface (18) of the body (10) or as a current loop extending on a side wall of the body (10) and coupling to the magnetic field.

Waveguide oscillator tunable through integrated varactor diode and

An integrated millimeter-wave transceiver comprising a substrate on which is provided an annular slot antenna (D) and a balanced mixer (F). Transmitter power is applied to one point of the antenna and the balanced mixer (F) is coupled to a second point of the antenna, the second point being orthogonal to the one point in the plane of the antenna. The coupling of the balanced mixer to the second point is by way of a coplanar waveguide (C). A short circuit (H) in the coplanar waveguide (G) at a quarter wavelength from the mixer prevents an even (asymmetric) mode on the coplanar waveguide from being propagated to the antenna. An IF signal is derived using an RF band stop filter (I).

Integrated millimeter-wave transceiver

A microwave patch antenna, comprising a substrate of high dielectric constant, an aperture in the substrate, a patch conductor positioned on one side of the conductor and juxtaposed over said aperture, a ground plane on the other side of the substrate and having an aperture juxtaposed to at least a substantial proportion of the patch conductor. A conductive cavity is RF-coupled to the ground plane at the aperture, the cavity extending away from the substrate and being short-circuited at its end remote therefrom; in the operating frequency range of the antenna, the cavity forms a waveguide constituting an inductance. The length of the cavity may be adjustable to tune the antenna, the length of the cavity being sufficient for the resonant frequency of the antenna to decrease with increasing cavity length.

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Crawley, United Kingdom

David Hillary Evans