A system, method, software and related functions are provided for managing activity in a radio frequency band that is shared, both in frequency and time, by signals of multiple types. An example of such a frequency band is an unlicensed frequency band. Radio frequency energy in the frequency band is captured at one or more devices and/or locations in a region where activity in the frequency band is happening. Signals occurring in the frequency band are detected by sampling part or the entire frequency band for time intervals. Signal pulse energy in the band is detected and is used to classify signals according to signal type. Using knowledge of the types of signals occurring in the frequency band and other spectrum activity related statistics (referred to as spectrum intelligence), actions can be taken in a device or network of devices to avoid interfering with other signals, and in general to optimize simultaneous use of the frequency band with the other signals. The spectrum intelligence may be used to suggest actions to a device user or network administrator, or to automatically invoke actions in a device or network of devices to maintain desirable performance.

System and method for management of a shared frequency band

An intelligent spectrum management (ISM) system and method are provided that includes sophisticated features to detect, classify, and locate sources of RF activity. The system comprises one or more sensors positioned at various locations in a region where activity in a shared radio frequency band is occurring and a server coupled to the sensors. Each sensor monitors communication traffic, such as IEEE WLAN traffic, as well as classifies non-WLAN signals occurring in the frequency band. The server receives data from each of the plurality of sensors and that executes functions to process the data supplied by the plurality of sensors. In particular, the server aggregates the data generated by the sensors and generates event reports and other configurable information derived from the sensors that is interfaced to a client application, e.g., a network management station.

Server and multiple sensor system for monitoring activity in a shared radio frequency band

A system and method are provided for managing communication with a plurality of wireless client devices operating in a radio frequency band shared by other types of devices, comprising a step of controlling at least one parameter associated with radio communication with each of the plurality of wireless devices based on the radio frequency environment associated with each corresponding one of the plurality of wireless client devices. Spectrum profile information describing the radio frequency environment (activity in the frequency band) at a wireless client device is sent to the wireless base station device (where the parameter controls are made) from either a wireless client device or another radio device in the proximity of one or more wireless client devices that is capable of generating the spectrum profile information. The spectrum profile information may include information identifying signals that are occurring in the frequency band in the proximity of a wireless client device. Examples of parameters that may be controlled at the wireless base station device include packet fragmentation threshold (the length of a data packet), transmission data rate and transmission scheduling (synchronizing a transmission to quiescent intervals of one or more periodic interfering signals).

System and method for management of a shared frequency band using client--specific management techniques

An electronic device provides a capability of distinguishing between human tissue and a non-human object in proximity of a transmission source. In this manner, transmission power adjustments to the transmission source can be made selectively, depending on whether human tissue or a non-human object is detected in the proximity of the RF transmitter. Distinguishing between human tissue and other non-human-tissue objects in proximity of the transmission source provides for selective control of SAR adjustments. Accordingly, an electronic device can avoid certain communication performance reductions introduced by decreases in transmission power effected to comply with SAR standards by reducing transmission power when human tissue is detected in the proximity but not reducing transmission power when a non-human object (but no human tissue) is detected in the proximity.

Selective specific absorption rate adjustment

An intelligent spectrum management (ISM) system and method that includes sophisticated features to detect, classify, and locate sources of RF activity. The system comprises one or more radio sensor devices positioned at various locations in a region where activity in a shared radio frequency band is occurring. A server is coupled to the radio sensor devices and aggregates the data generated by the sensor devices. Data collected and processed by the server from the sensors may be coupled to a console application that displays the data in desirable user interface format. According to one aspect, the server continuously stores spectrum analysis data pertaining to activity in a frequency band over time and/or protocol analysis data pertaining to analysis of packets transmitted in the frequency band according to a communication protocol. A console application includes a time-shift display mode that permits a user to specify an instant of time prior to the current time from which to playback spectrum analysis data and/or protocol analysis data generated by one or more radio sensor devices.

User interface and time-shifted presentation of data in a system that monitors activity in a shared radio frequency band

A predistortion technique for high power amplifiers includes an adaptive predistortion algorithm that operates independently of data samples to write a set of complex gain values, or predistortion parameters, to a lookup table. The algorithm may be processor-driven. The gain values are taken from the lookup table and multiplied by a complex digital baseband waveform. The gain values may first be subjected to interpolation. The downconverted output of the amplifier is measured to gauge the efficacy of the predistortion. Based on the effect of the predistortion upon the ratio of in-band power to out-of-band power, decisions are made on the set of predistortion parameters for the next iteration of the algorithm. The algorithm runs continuously, perturbing parameters and adapting the predistortion functions accordingly in an effort to continually reflect instantaneous amplitude-modulation and phase-modulation relationships that may change over time with temperature variation or component aging.

Predistortion technique for high power amplifiers

Certain aspects of the present disclosure propose methods for determining power level of one or more transmitters based on a power level of a primary transmitter when the transmitters are located in close proximity of each other. The power levels may be determined such that a combined power of all the transmitters is compliant with regulatory radio frequency (RF) safety requirements. For certain aspects, power level of the lower priority transmitters may be determined utilizing one or more look-up tables. For another aspect, power level of the lower priority transmitters may be calculated using an algorithm based on the power level of the priority transmitter. In aspects, the power level of lower priority transmitters and the time duration for which the transmitters are active may be selected dynamically so that the time averaged power of the transmitters for a defined period of time falls below the RF exposure limit.

Apparatus and method for adjustment of transmitter power in a system

In a code division multiple access (CDMA) spread spectrum cellular communication system in which a mobile station user communicates with another system user via at least one base station, wherein each base station transmits a common pilot signal of a different PN offset with respect to other base stations in said system, a method for merging neighbor lists to account for false indications of signal strength due to topography. The merged list, included as part of the Neighbor List Update Message, is arrived at by first measuring pilot signal strengths and phase delays received by the mobile station and reporting this information to the mobile telephone switching office. At the mobile telephone switching office, pilots whose phase delay indicates a large round trip delay time are ignored in subsequent calculations. Then a neighbor list union is generated as the union of all predetermined neighbor lists corresponding to said received pilot signals. Each member, or base station, in the neighbor list union is operated on by a weighting function which takes into account how often each member is included in each received pilot's predetermined neighbor list and the signal strength of such pilots. The relative weights are then sorted and the highest ranking members form the Neighbor List Update Message, up to a predetermined number of members.

Method and apparatus for merging neighbor lists in a CDMA mobile telephone system

A method and apparatus for use in a wireless communication base station which provides real-time, continuous detection of in-band jammers with negligible impact on base station cost. In addition to providing jammer detection, the use of the invention to provide improved hardware and system diagnostic capabilities is presented. The jammer detection apparatus utilizes automatic gain control techniques, digital sampling, and digital signal processing to identify anomalous frequency components in the received power spectral density curve. Also described are the use of complex sampling, the complex fast Fourier transform (FFT), and Hanning windows to improve jammer detection capabilities. A method of estimating the location of in-band jammers is described using the computed received power spectral density curves of multiple base stations.

Method and system for detecting in-band jammers in a spread spectrum wireless base station

A detector (36) is used to sample of set of power measurements of a receive signal. The receive signal may comprise one or more signals from remote users as well as interference. A variance of the set of power measurements is also determined. The variance is compared to an overload threshold value. If the variance exceeds the overload threshold value, for some period of time, the system is declared to be operating at a potentially unstable point. In this state, future connection originations are denied.

Walid Hamdy

Papers

Predistortion technique for high power amplifiers

Apparatus and method for adjustment of transmitter power in a system

Method and apparatus for merging neighbor lists in a CDMA mobile telephone system

Method and system for detecting in-band jammers in a spread spectrum wireless base station

Method and apparatus for reverse link overload detection