Showing papers by "Aarno Parssinen published in 2008"

Method, apparatus and computer program for sensing spectrum in a cognitive radio environment

Abstract: To find frequency slots over which a cognitive radio can send an opportunistic transmission, a wideband spectrum is searched with a lower resolution to identify bandwidth slices having low or no signal levels. The identified bandwidth slices are searched with a higher resolution and candidate frequency slices are selected as those bandwidth slices having the least signal levels after the higher resolution searching, and ranked from the lowest signal level to the highest. A spectrum detection algorithm is executed on the selected candidate frequency slices in the order of the rank until it is decided that one of them has sufficiently free spectrum. A transmission is then opportunistically sent on the decided candidate frequency slice. Ongoing to the searching, intermittent signals are detected and a band about them is searched with the lower resolution to determine if the band about the detected intermittent signal is an identified bandwidth slice. Various techniques are shown for how the fine search is conducted.

Direct-digital RF-modulator: a multi-function architecture for a system-independent radio transmitter

Abstract: The number of different radio systems is currently increasing in portable devices like mobile phones due to the wider range of applications that require an optimized wireless communications channel to different services or other devices. To make this cost and power efficient, the transmitter must be adaptable to several different radio systems while keeping the complexity and cost reasonable. This article presents fundamental circuit techniques to enable low cost, low power, and low complexity transmitter architecture by combining digital-to-analog conversion, up-conversion, unwanted sideband rejection, power control, and part of the digital image rejection filtering into a single mixed-signal circuit block. The direct-digital RF-modulator architecture is the basis for a software-defined radio transmitter. It was demonstrated against WCDMA system requirements, but the versatility and the performance of this architecture enables support for other radio systems, such as GPRS and WLAN.

A New Symmetric Transceiver Architecture for Pulsed Short-Range Communication

Abstract: This paper proposes a novel symmetric super- regenerative transceiver architecture for pulsed short-range communication. The proposed architecture is targeted for wireless applications where ultra low power consumption and data-rate in tens of megabits per second are needed over distances in the range of tens of centimeters. The transmitter and receiver are both based on super-regenerative principle and both functions in the transceiver utilize one mutual super-regenerative oscillator. Additionally, the transceiver architecture allows fast synchronization of transceivers thanks to the delayed reflection phenomenon which makes it possible to detect correct timing simultaneously at both ends of the system. Measurement results demonstrate the feasibility of the proposed principle.

Method and apparatus to operate a cognitive radio in a crowded collaborative system

Abstract: In a cognitive radio environment with at least three cognitive radio terminals, terminals 1 and 2 have an active link. Terminal 3 estimates the link quality, and if it is deemed good terminal 3 transmits over the frequency band in use on the link. Terminal 3 then monitors the link between terminals 1 and 2 to quantify its interference on it. If no interference is detected terminal 3 can increase its power. If terminals 1 and 2 change their modulation terminal 3 deems its interference too severe and either reduces power or finds another frequency band. Terminal 3 can use blind modulation detection for the link between terminals 1 and 2, and estimate link quality based on the type of modulation in use.

A radio frequency apparatus

Abstract: An apparatus for controlling at least one radio module, wherein the apparatus is configured to generate at least one service request for a first radio mode, determine at least one logical architecture model dependent on each service request, select at least one of the plurality of radio modules to form a physical architecture structure dependent on each logical architecture model, and generate at least one configuration data set dependent on the selected one of the plurality of radio modules.

Configuring a modular radio frequency communications device

Abstract: Controlling a plurality of radio modules, by generating at least one service request for a first radio mode, determining at least one logical architecture model dependent on each service request, selecting appropriate radio modules to form a physical architecture structure dependent on each logical architecture model, and generating at least one configuration data set dependent on each selected radio modules. The configured radio modules may comprise a multi-radio communications device, such as a cellular phone, with software defined radio (SDR) operation.