6994 results about "Interference (communication)" patented technology

Exploiting the substantive reciprocity of internode channel responses through dynamic, adaptive modification of receive and transmit weights, enables locally enabled global optimization of a multipoint, wireless electromagnetic communications network of communication nodes. Each diversity-channel-capable node uses computationally efficient exploitation of pilot tone data and diversity-adaptive signal processing of the weightings and the signal to further convey optimization and channel information which promote local and thereby network-global efficiency. The preferred embodiment performs complex digital signal manipulation that includes a linear combining and linear distribution of the transmit and receive weights, the generation of piloting signals containing origination and destination node information, as well as interference-avoiding pseudorandom delay timing, and both symbol and multitione encoding, to gain the benefit of substantive orthogonality at the physical level without requiring actual substantive orthogonality at the physical level.

A receiver of the present invention addresses the need for improved interference suppression without the number of transmissions by the power control system being increased, and, to this end, provides a receiver for a CDMA communications system which employs interference subspace rejection to tune a substantially null response to interference components from selected signals of other user stations. Preferably, the receiver also tunes a substantially unity response for a propagation channel via which a corresponding user's signal was received. The receiver may be used in a base station or in a user/mobile station.

The present invention provides methods and apparatuses for utilizing unused portions of an allocated frequency spectrum in a wireless communications system that broadcasts content to wireless stations. A first wireless station may communicate with a second wireless station on an idle broadcast channel while keeping the resulting interference level below an acceptable maximum limit at the other wireless stations. Using interference level information that are measured at the wireless stations, the wireless station can negotiate with the other wireless station on an establishment channel for subsequent communications on one or more broadcast channels. The wireless station may receive broadcast content on a time slice that corresponds to a broadcast channel and that is further processed by the wireless station. Otherwise, the wireless station can utilize the corresponding time to measure an interference level for the corresponding channel or to transmit or receive data to/from another wireless station.

An RFID reader for use in a security system based upon RFID techniques. The RFID reader can use power line carrier communications to communicate with the controllers in the security system. The RFID reader of the security system can be provided with multiple modulation techniques, multiple antennas, and the capability to vary its power level and carrier frequency. The controller of the security system determines which RFID readers may transmit, at what times, and the parameters with which to transmit. The RFID reader can detect interference or jamming, and respond. The RFID reader can transmit RF energy useful for detecting motion or for charging the batteries in RFID transponders. The RFID reader can receive wireless communications from active transmitters or from other RFID readers.

A method, communication apparatus, and machine-readable medium to transmit a downlink signal in a substantially non directional manner from a first communication station of a communication system on a first downlink conventional channel. The first communication station includes a smart antenna system having a plurality of antenna elements. The method includes providing a first set of sequential time intervals for the communication device for communication with its remote communication devices. One or more remote communication devices of the communication system known to the first communication station to be undesired remote communication devices transmit a signal on a first uplink conventional channel. The signals transmitted are received. In one version, they are received at the first communication station, and in another version, by another communication station of the communication system. The signal received are used to configure the smart antenna system for transmitting a downlink signal in a non-directional manner that includes mitigating interference towards the undesired remote communication devices on the first downlink conventional channel.

Methods and apparatus are described for mitigating intercell interference in wireless communication systems utilizing substantially the same operating frequency band across multiple neighboring coverage areas. The operating frequency band may be shared across multiple neighboring or otherwise adjacent cells, such as in a frequency reuse one configuration. The wireless communication system can synchronize one or more resource allocation regions or zones across the multiple base stations, and can coordinate a permutation type within each resource allocation zone. The base stations can coordinate a pilot configuration in each of a plurality of coordinated resource allocation regions. Subscriber stations can be assigned resources in a coordinated resource allocation region based on interference levels. A subscriber station can determine a channel estimate for each of multiple base stations in the coordinated resource allocation region to mitigate interference.

A wireless communication system can implement beamforming across multiple omni-directional antennas to create beams at different spatial directions. The communication system can arrange the beams in sets, with each set arranged to provide substantially complete coverage over a predetermined coverage area. The communication system can arrange the multiple SDMA beam sets to support substantially complementary coverage areas, such that a main beam from a first set provides coverage to a weak coverage area of the second beam set. The wireless communication system assigns or otherwise allocates substantially orthogonal resources to each of the beam sets. The wireless communication system allocates resources to a communication link using a combination of beam sets and substantially orthogonal resources in order to provide improved coverage without a corresponding increase in interference.

A wireless communication system includes a first channel state measurer and a second channel state measurer. When a second communication device measures a state of a channel between the second communication device and a first communication device using reference signals transmitted from the first communication device, the first channel measurer is configured to measure a state of the channel including an interference due to a signal transmitted from another first communication device. When measuring the state of the channel between the second communication device and the first communication device using the reference signals transmitted from the first communication device, the second channel state measurer measures the state of the channel while suppressing the interference due to the signal transmitted from the another first communication device. Accordingly, the wireless communication system can generate adequate feedback information both when cooperative communication is performed and when cooperative communication is not performed.

The invention provides a base-station (BS)-combined direct-through terminal optimized resource allocation method in a direct-through cellular system. In order not to interrupt the normal communication of traditional cellular subscriber links and obtain effective gain brought by device-to-device (D2D) direct-through technology, D2D subscribers are allowed to adopt a resource allocation manner that resources are selected by a D2D subscriber end when uplink and downlink resources of the cellular system are shared; at this time, the D2D subscribers only need to consider the interference to other cellular subscribers (CUs) arising from signals of the D2D subscribers; and meanwhile, a BS centralized-control manner is adopted to carry out resource allocation, the centralized-control advantage of a BS is exerted, a BS and D2D terminal combined optimization manner is fully utilized, and the advantages of the two allocation manners are exerted. The BS-combined direct-through terminal optimized resource allocation method in the direct-through cellular system has the advantages that the resource utilization ratio and availability of a coexistent system which is provided with the D2D direct-through technology are sufficiently improved, the multiplexing gain of the resources are maximally developed, the system capacity is increased, the service types are increased, and the quality of service is ensured; and many chances for resource multiplexing are developed under the condition of limited resources from a novel resource allocation viewing angle.

Improved pilot signal sequences which facilitate multiple channel quality measurements, e.g., through the use of different signal pilot transmission power levels, are described. In various implementations the transmitted pilot sequences facilitate determining the contribution of interference from other sectors of a cell using the same tones, e.g., in a synchronized manner, as the sector in which the pilot signal measurements are being made. To measure noise contributions from neighboring sectors a sector NULL pilot, e.g., a pilot with zero power, is transmitted in an adjacent sector at the same time a pilot signal with a pre-selected, and therefore known, non-zero power is transmitted in the sector where the received pilot signal measurement is made. To facilitate background noise measurements, a cell NULL is supported in some embodiments. In the case of a cell NULL, all sectors of a cell transmit a Null pilot, on a tone that is used to measure background noise. Since no power is transmitted in the cell on the tone during the measurement, any measured signal on the tone is attributable to noise, e.g., background noise which may include inter-cell interference.

Methods and apparatus for high throughput wireless cells and networks are described. The wireless cells may be equipped with multiple radios. Antennas may be arranged into overlapping and non-overlapping patterns. Channels may be assigned to foster servicing clients, and inter-cell communication. Attenuation may be used to decrease interference. Networks may be formed using a variety of methods and apparatus.

An inter-cell interference coordination method and apparatus is provided for a heterogeneous network system based on Orthogonal Frequency Division Multiplexing (OFMD) communication. The inter-cell interference coordination method and apparatus exchanges two different types of inter-cell interference coordination messages between base stations to adaptively use the frequency division and time division schemes, thereby coordinating inter-cell interference of control channels transmitted randomly in distributed manner.

A method for distributed spectrum management of digital communication systems having a plurality of communication lines on which signals are transmitted and received by respective users, the method comprising the steps of: collecting information about line, signal and interference characteristics of a plurality of the communication lines from a plurality of sources; determining the line, signal and interference characteristics of a plurality of the communication lines; varying power allocation of particular plurality of the communication lines between respective transmitter and receiver taking into consideration the determined line, signal and interference characteristics of a plurality of the communication lines and consideration of a noise weight of a plurality of the communication lines to enable a minimum power on a plurality of the communication lines and to allow required effective data-rates for each of said respective users to be satisfied.

Apparatus and methods for improving the throughput and capacity of a wireless communications network. In one embodiment, this improvement is accomplished by focusing upon reduction of the co-channel interference, including the interferences that are unpredictable or undetectable to a traditional network. Various implementations detect the receiver interference (i.e. the interference affecting the receiver performance) at the transmitting node in order to avoid or reduce its effect at the receiving node. This detection can be as simple as e.g., spectral sensing constituting power measurement, and/or can be more sophisticated such as measurements including bandwidth, duty cycle and statistical behavior of the unwanted signal.

A method for cancelling co-channel interference in a multi-carrier communication system includes receiving a serial baseband multi-carrier signal including at least one desired signal and at least one interference signal over at least one receiving branch, and converting the received multi-carrier signal into a plurality of baseband sub-carrier signals. Co-channel interference in each sub-carrier signal is cancelled by subtracting an estimated desired received sub-carrier signal and an estimated interference sub-carrier signal from a received sub-carrier signal. The sub-carrier signals are converted to a multi-carrier output signal comprising the desired signal.

The present invention provides an active radio frequency identification (RFID) tag and an application system and method thereof. The system includes: a control processor; a coordinator; an active RFID tag, configured to perform an RF feature check first with very little time before spending more time to receive a whole valid data packet during the time period of an interception state; and a reader/writer. Therefore, the power consumption of an active RFID tag is reduced drastically. Further, the present invention also provides an active RFID tag having a plurality of fixed mode actions and the application system and method thereof, thereby improving the communication efficiency of the radio communication system and effectively reducing the probability of signal collision and mutual interference.

A system and method for classifying channels in a frequency hopping wireless communication system is provided. A data collection engine operates to obtain channel metrics indicating the level of interference for each channel used by the wireless communication system. A data analysis engine operates to provide a channel map for adaptive frequency hopping (AFH) and/or a channel map for channel avoidance. More specifically, the data analysis engine first operates to filter the channel metrics to remove channel metrics indicative of frequency hopping interference. Next, the channels are divided into a number of channel blocks each including at least two adjacent channels. For each channel block, the channel metrics of the channels within the channel block are combined to provide a metric sum. The data analysis engine then operates to classify each channel as usable or unusable based on the metric sums for each of the channel blocks.