1294 results about "Cognitive radio" patented technology

A method of determining operating parameters for a secondary system transmitter is described. The transmitter characteristics, including location and operating frequency band, are provided to a geo-location database. The database determines the maximum allowable transmission power that meets various specifications for different channels and conveys the power and channel(s) to the transmitter. The database estimates channel incumbent signal strengths based on the transmitter location and primary and higher-priority secondary incumbent systems, estimates the splatter levels, determines whether adjacent and co-channel interference protection ratios are met, and adjusts the allowable power level accordingly. The database also estimates aggregate co- and adjacent channel primary and secondary incumbent system interference levels at the transmitter location and predicts channel quality for each allowable channel. The estimated levels are updated using measurements of actual levels at the transmitter location. The database dynamically allocates channels using the secondary system priorities.

A method, wireless controller, and information processing system are provided to dynamically allocate spectrum sensing resources. A first input (804) including available sensing session time for performing spectrum sensing with respect to one or more primary systems (102) is received. A second input (806) including a set of communication channels to be monitored in the spectrum sensing session is received. A third input (808) including detection constraints associated with a plurality of available sensing nodes (114) in a secondary network (104) for performing the spectrum sensing is received. Spectrum sensing resources are dynamically allocated (814) among a set of the plurality of available sensing nodes (114) based on the first (804), second (806), and third inputs (808).

A cognitive radio system includes: a state detecting device that scans a frequency band allocated to another radio system than the cognitive radio system to detect a first use-state of the frequency band; a first server including a first gathering unit that receives first information relating to the first use-state and a second gathering unit; a second server that stores a second use-state of the frequency band allocated to the other radio system, the second server configured to provide second information relating to the second use-state to the second gathering unit; and a notifying unit that notifies a terminal device in the cognitive radio system of information of an available channel based on the first information and the second information.

A technique for spectrum sensing management and control for a secondary communication system seeking to utilize another communication system's spectrum is provided (600). Sensor control data is sent from a base station to subscriber units (604). Sensing measurements are taken and sent back to the base station for ranking (608) as sensed feedback information. Comparisons of the sensed feedback information are made to each other and to thresholds aligned with the types of measurements taken (610). An initial ranked channel list is generated (612). Weighting of the initial ranking list and secondary ranking list is followed by re-ranking the channels according to the weighting into a final ranking list (612). The final ranking list is transmitted to the mobile units to enable operation within the other communication system's spectrum within interfering with that system (614). The weighting is based on the type of sensing measurement taken as opposed to the channel.

A method of partitioning resources in a CR wireless communication system and a system supporting the same are provided. A new BS receives radio resource status information from a prior BS using a particular frequency band, and requests resource partitioning to the prior BS using a new uplink subchannel defined for communications between BSs. Resource negotiation messages are exchanged over a channel defined between the two BSs so as to efficiently partition resources between the BSs.

A resource management method in a Cognitive Radio communication system where at least two Base Stations of heterogeneous networks provide a connection service to Mobile Stations within their service areas is provided. In the method, at least one BS having candidate resources broadcasts its candidate resource information on the downlink of a system information channel. At least one BS lacking in resources searches the downlinks of system information channels from neighbor heterogeneous networks, selects an offer BS among the BSs having candidate resources, and rents resources from the selected offer BS by negotiations.

In order to satisfy the conflicting requirements for spectrum sensing and QoS of data transmission, it is highly desirable for a cognitive radio system, e.g. IEEE 802.22 WRAN, to perform spectrum sensing and data transmission simultaneously. Embodiments of the invention address critical issues of self-interference generated from a transmission unit to the co-located sensing unit when the simultaneous sensing and data transmission technique is applied. A number of interference mitigation techniques are described and analyses are given.

The invention relates to a cognitive radio (CR) WiFi network which includes a plurality of radio environment aware WiFi terminals, which collect local WiFi interference information and send this information to a CR network management system (NMS). The CR NMS includes a database for storing historical records of the interference information obtained from the terminals, and cognitive engines for analyzing the stored historical interference records and determining terminal-specific transmission and reception parameters. In one embodiment the network implements a deterministic NMS-directed networks-wide TDD/TDM scheduling of WiFi communications for optimal channel re-use and interference avoidance, and a novel terminal synchronization mechanism.

This invention relates to cognitive radio based wireless communications of dynamic spectrum access networks, and more particularly to a method of addressing radio frequency sensing control and dynamic frequency selection control. A method called Cognitive Dynamic Frequency Hopping that is based on the selective Simultaneous Sensing and Data Transmissions is described. The Cognitive Dynamic Frequency Hopping method is further facilitated by a collision avoidance technique. The described method satisfies both reliable and timely RF sensing for guaranteeing licensed user protection, and QoS satisfaction for services of the dynamic spectrum access systems.

An apparatus and method for signal detection in a CR-based wireless communication system are provided. In the signal detection apparatus, a cyclic power calculator calculates the power spectral density of a cyclo-stationary and periodical signal to be detected with respect to a cyclic frequency and calculates optimum statistics using the power spectral density. A signal detector determines whether a signal exists or not according to the optimum statistics.

A signaling method between a cognitive radio (CR) base station and a CR terminal in a CR environment, and a channel division method used for the signaling method, includes: detecting a channel usage of an incumbent system, which communicates with a CR base station; sensing an outband channel to communicate with the CR base station; receiving an EOS, which is broadcasted from the CR base station via the outband channel according to a predetermined period; and transmitting a sensing report signal with respect to the channel to the CR base station.

In a non-limiting and exemplary embodiment, a method is provided for sharing secondary cognitive radio resource user related information. A coexistence node receives information on network properties associated with secondary cognitive radio resource users. An upload message is generated and sent, the upload message including for a secondary user database at least information on the received network properties associated with secondary cognitive radio resource users. A location-dependent network map including at least information on network properties is generated. The network map is sent to assist one or more secondary cognitive radio resource users.

Dynamic frequency selection based on CR is provided. A CR BS detects an interference-free and unused frequency band. When sensing a new BS that has great signal strength and requires the frequency band during communications in the frequency band, the CR BS releases the frequency band and dynamically selects another frequency band to avoid interference.

A method detects unused frequency bands in a cognitive radio network. Multiple frequency bands for RF signals are sensed using an antenna array including a plurality of elements coupled to a receive RF chain, in which the plurality of elements are individually controllable. For each frequency band, multiple spatial directions are sensed for the RF signals using the antenna array. A particular frequency band and a particular direction and a particular time slot are assigned as an available frequency band, an available direction and a particular time slot for transmitting RF signals in a cognitive radio if the RF signals are not sensed in the particular spatial direction for the particular frequency band, and in which the RF signals are transmitted by a transmit chain connected to the antenna array.

There is provided a system and method of sensing a radio frequency channel to determine activity, determining location, mapping location to existing radio frequency licenses, determining the radio frequency channel to be available and sharing that the radio frequency channel is available. Systems implementing this method may use a single device to perform the method steps or may use several different devices to share the complexity and workload associated with the method. This method is applicable to white space radio and to cognitive radio.

A system and method for delivery of high speed data services over dedicated and non-dedicated private land mobile radio (PLMR) channels using cognitive radio technology. The PLMR system provides bi-directional Point-to-Multipoint (PtMP) data communication between a dispatch center and many fixed or mobile remote terminals. A plurality of base stations communicate with a base station controller at the dispatch center and a plurality of remote radios communicate with at least one of the remote terminals. PLMR channel scanners, located in each base station and remote radio, scan the PLMR channels to determine which of the PLMR channels is idle at any point of time so that data communication may take place.

A cognitive radio wireless device (114) dynamically manages signal detection in a cognitive radio system (100). Spectrum sensing is performed for a first sensing frame on at least one communication channel. At least one observed signal is received (204) on the at least one communication channel. A detection decision (210) is performed to determine if the observed signal is noise or an active signal associated with an active user. The detection decision (210) is performed by comparing observed signal energy estimation with a current detection threshold. The current detection threshold can be an arbitrarily defined threshold or a detection threshold based on a previous detection decision for a sensing frame immediately prior to the first sensing frame.

A communication initialization method at a MAC layer in a CR wireless communication system is provided. The use or non-use of a frequency band is sensed over a broadband with a minimized sensing time in a non-interfering manner with existing communication systems.

Spectrum-sensing algorithms and methods may be provided for use in cognitive radios and other applications. The spectrum-sensing algorithms and methods may include receiving an input spectrum having a plurality of channels, performing a coarse scan of the plurality of channels of the input spectrum to determine one or more occupied candidate channels and vacant candidate channels, where the coarse scan is associated with a first resolution bandwidth and a first frequency sweep increment, performing a fine scan of the occupied candidate channels and the vacant candidate channels to determine actually occupied channels and actually vacant channels, where the fine scan is associated with a second resolution bandwidth and a second frequency sweep increment, and storing an indication of the actually occupied channels and the actually vacant channels.