Abstract: A network coordinator can assign an association identifier (AID) and/or a group identifier (GID) to identify a client station to which a packet is to be transmitted and to enable the client station to determine whether to receive an incoming packet. The network coordinator can randomly generate a base AID that is representative of the network coordinator and can assign at least one AID to client stations to minimize the probability of client stations associated with proximate network coordinators being assigned the same AIDs. The network coordinator can also randomly assign at least one GID to a group of client stations to minimize the probability of groups of client stations associated with the proximate network coordinators being assigned the same GID. The client station can analyze indications of a received AID and/or received GID to determine whether to receive the packet or whether to switch to an inactive power state.

Abstract: A mechanism for mitigating inter-user interference in a multi-user wireless communication environment is disclosed. A first network device determines a plurality of steering matrices, associated with a corresponding plurality of subcarriers, for each of multiple destination devices associated with the first network device. A phase difference between corresponding steering vectors of each pair of consecutive steering matrices of the plurality of steering matrices associated with each of the destination devices is determined and phase rotation is performed to maintain phase continuity between the consecutive steering matrices. One or more pre-coding matrices are calculated based on at least a subset of the plurality of steering matrices associated with the multiple destination devices. The one or more pre-coding matrices are applied to data to be transmitted to the multiple destination devices to mitigate interference between each of the multiple destination devices.

Abstract: A routing system can be configured to determine a route based on availability and reliability of location reference devices to determine a most reliable route between a source and a destination. Visibility information that is indicative of availability of at least a threshold number of location reference devices along the route can be determined. For each of a plurality of routes between the source and the destination, a reliability rating associated with the route can be determined based on the visibility information associated with the route. The reliability rating is indicative of a reliability of the route and an ability of the routing system to maintain continuous connectivity to the at least the threshold number of location reference devices along the route. The reliability ratings of the plurality of routes are compared to identify and to present one of the plurality of routes with a highest reliability rating.

Abstract: Wired and wireless communication networks can be subject to burst interference resulting in loss of throughput and data corruption. In a communication system comprising a transmitting network device and a receiving network device, the transmitting network device can be configured to implement a dynamic bit allocation technique for retransmitting packets of a failed packet transmission. On receiving a request for retransmission from the receiving network device, the transmitting network device can dynamically allocate bits of original symbols across two or more constituent symbols per original symbol. The transmitting network device can allocate the two or more constituent symbols across one or more retransmission packets to exploit time diversity. The transmitting network device can also vary modulation and coding schemes and other transmit parameters to generate robust retransmission packets.

Abstract: Wired and wireless communication networks can be subject to burst interference resulting in loss of throughput and data corruption. In a communication system comprising a transmitting network device and a receiving network device, the transmitting network device can be configured to implement balanced bit loading for retransmitting packets of a failed packet transmission. On receiving a request for retransmission from the receiving network device, the transmitting network device can identify and eliminate sub-carriers that are associated with a bit load that is less than a predefined bit load threshold. The transmitting network device can attempt to reallocate bit loads of the eliminated sub-carriers to remaining sub-carriers across two or more constituent symbols per original symbol.

Abstract: A mechanism for processing beamforming steering matrices in a transceiver system. A plurality of beamforming steering matrices associated with a plurality of subcarriers of an RF signal received at the transceiver system are generated. The beamforming steering matrices are compressed and stored. The beamforming steering matrices may also be grouped or sub-sampled prior to being stored. The beamforming steering matrices are decompressed and ungrouped before being applied to data to be transmitted. Prior to ungrouping the beamforming steering matrices, a phase difference between corresponding beamforming steering vectors of consecutive beamforming steering matrices is determined. Phase rotation is performed on the corresponding beamforming steering vectors based on the determined phase difference associated with the corresponding beamforming steering vectors to improve phase continuity between consecutive beamforming steering matrices.

Abstract: Unscheduled transmissions of one wireless network device while a collocated wireless network device has control of a communication medium can corrupt packets received by the collocated wireless network device. Interference between the collocated wireless network devices can lead to degradation in performance of either/both the wireless network devices. In a communication system comprising a first wireless network device collocated with a second wireless network device, the first wireless network device can be configured to transmit a coexistence message to the second wireless network device when the first wireless network device transmits a packet without control of the communication medium. On receiving the coexistence message indicating that the first wireless network device transmitted a packet without control of the communication medium, the second wireless network device can discard any packets received at the second wireless network device and can request retransmission of the discarded packets.

Abstract: This disclosure involves methods and systems for controlling WLAN and Bluetooth communications by allocating bandwidth into times blocs having a first segment with Bluetooth priority and a second segment with WLAN priority. Access to the wireless communication medium is signaled over an interface connecting the WLAN and Bluetooth modules. Downlink traffic is modulated by signaling the WLAN access point to buffer traffic during the first segment. WLAN traffic can also be modulated by allowing reception and blocking transmission WLAN signals during the first segment. Further, while high priority Bluetooth transmission are preferably always allowed, low priority Bluetooth transmission can be restricted during the second period, depending upon the respective states of the WLAN and Bluetooth modules. A coexistence agent can be used to transfer relevant information between the WLAN and Bluetooth modules.

Abstract: A satellite navigation receiver having a flexible acquisition and tracking engine architecture. The flexible acquisition engine has a reconfigurable delay line that can be used either as a single entity or divided into different sections. Consequently, it can be configured to search different satellite vehicles, a single Doppler frequency, and full CA code in parallel. When configuring the delay line into different sections, each section is used to search a partial CA code. In this configuration, multiple Doppler mode, multiple satellite vehicles, multiple Doppler frequencies, and partial CA code can be searched in parallel. Furthermore, the different sections of the CA code can be time-multiplexed into a correlator, which can then be over clocked to achieve full CA code correlation. The flexible tracking engine includes a number of parallel tracking channels, whereby each individual channel has a number of taps or fingers, which can be used to lock onto different delays.

Abstract: A technique for improving frequency synthesizer performance by frequency-compensating charge pump current in order to maintain a consistent loop bandwidth over a wide operating frequency range is described. A relationship between the capacitance value associated with a voltage controlled oscillator resonant tank and the magnitude of current pulses in a related charge pump is exploited to bound the loop bandwidth of the frequency synthesizer over both operating frequency and process variation. A control state machine generates digital coarse tune values that dynamically select a capacitance for the resonant tank, such that the voltage controlled oscillator operates within an optimal control voltage range. Each dynamically selected capacitance value is then used to determine the magnitude of current pulses in the charge pump.

Abstract: Current OFDM systems use a limited number of symbols and/or sub-channels to provide approximations for channel estimations and pilot tracking, i.e. phase estimations. For example, two training symbols in the preamble of a data packet are used to provide channel estimation. Four of the fifty-four sub-channels are reserved for providing phase estimation. However, noise and other imperfections can cause errors in both of these estimations, thereby degrading system performance. Advantageously, decision feedback mechanisms can be provided to significantly improve channel estimation and pilot tracking in OFDM systems. The decision feedback mechanisms can use data symbols in the data packet to improve channel estimation as well as data sub-channels to improve pilot tracking.

Abstract: A system and method are described for repeatedly and efficiently performing a wireless communication channel survey to determine whether comparable communications devices exist, which frequencies are in use, and the identities of the comparable communications devices. A beacon data table stores received beacon data which is used to predict beacon arrival times, thereby allowing a receiver to be tuned away from an active data communications channel for a shorter dwell time than a beacon period. A further efficiency can be gained if beacon generators cooperatively stagger their beacon times according to one or more measurable characteristics of the beacon generator, e.g. the operating channel number and the SSID.

Abstract: A timing circuit for generating asynchronous signals is provided that uses minimal area while maximizing speed. This timing circuit can include a timing control block and disable/enable circuitry. The timing control block can include an SR latch and first and second delay blocks. The SR latch can generate first and second signals, wherein the first and second signals are asynchronous. The first delay block can generate a delayed first signal and provide that signal to a first input terminal of the SR latch. Similarly, the second delay block can generate a delayed second signal and provide that signal to a second input terminal of the SR latch. Notably, the first and second delay blocks delay positive going edges of the first and second signals differently than negative going edges of the first and second signals.

Abstract: A system may include a first circuit configured to generate a first clock having a first period of oscillation, and a second circuit configured to generate a second clock having a second period of oscillation, where the difference (?T) between the first period of oscillation and the second period of oscillation remains within a specified limit even during variations in temperature and/or during variations in the supply voltage. The system may further include a control circuit, which may receive the first clock and the second clock, and adjust, according to ?T, a first target parameter corresponding to a first number of cycles of the first clock, when a current cycle count of the second clock reaches a second target parameter corresponding to a second number of cycles of the second clock.

Abstract: A method of generating a quadrature local oscillator (LO) frequencies is provided. In this method, a voltage-controlled oscillator (VCO) frequency can be mixed with a divided version of the VCO frequency to generate mixed signals. A lower sideband of the mixed signals can be selected for the quadrature LO frequencies to minimize the occurrence of spurs. Notably, the divided version is 1/N of the VCO frequency and the VCO frequency is a radio frequency (RF) channel frequency times a ratio N/(N?1).

Abstract: Communicating among stations in a network includes providing repeated beacon transmissions from at least some of the stations including a first station. The first station is assigned to a first level. Any stations that can reliably receive transmissions from the first station are assigned to a second level. Any stations not assigned to any of the preceding levels that can reliably receive transmissions from the preceding level are assigned to each of one or more higher levels. Timing information at each station in a given level is synchronized according to transmissions received from at least one station in the preceding level.

Abstract: A method and apparatus for qualifying a Satellite Positioning System (SPS) location determination. A method in accordance with the present invention comprises determining a constellation of satellites used in the location determination, making a measurement set based on signals received from the constellation of satellites, comparing the measurement set and the constellation of satellites used in the location determination to a predetermined threshold, and reporting the location determination only when the threshold is not exceeded. Such a method further optionally includes the threshold being user-selectable, the threshold being adjusted or disabled based on a pre-defined scheme, the threshold being adjusted in a sequential form based on a pre-defined scheme, and the measurement set being made in a Global Positioning System (GPS) receiver.

Abstract: To provide an extra wide bandwidth communication using standard channels, multiple non-overlapping channels can be used. To provide a 40 MHz communication, two non-overlapping 20 MHz channels, i.e. a control channel and an extension channel, can be used to provide an effective 40 MHz channel. Advantageously, a wireless device can dynamically detect 20/40 MHz signals on a packet-by-packet basis, thereby facilitating commercially viable 40 MHz communication. The wireless device can monitor traffic on the extension channel to facilitate accurate 20/40 MHz decision making. Protection, e.g. legacy preambles and RTS/CTS headers, can be provided on the control and extension channels.

Abstract: A method for determining portions of a GPS satellite signal may use non-coherent integration to determine a repeated pattern such as a preamble. Once the repeated pattern is determined, portions of the GPS satellite signal that may be determined with partial correlation sums. Sensitivity to satellite signals may be increased by computing more partial correlation sums on portions of the GPS satellite signal. In one embodiment, time of day information may be determined from the GPS satellite signal with partial correlation sums.

Abstract: A signal analysis mechanism for processing and classifying an RF signal received at a WLAN device. A plurality of spectral data captures comprising time-frequency data and receive signal strength indicator (RSSI) data associated with the RF signal received at the WLAN device are generated. The time-frequency and RSSI data of each of the plurality of spectral data captures is processed to determine whether each spectral data capture is a narrowband signal capture. If the plurality of spectral data captures are narrowband signal captures, a narrowband interference signal type associated with the received RF signal is determined based, at least in part, on a plurality of parameters associated with the narrowband signal captures.