摘要:
An antenna is provided with an electronic component or circuit that has a value corresponding to properties of the antenna. A read mechanism reads the value and sets an operational status of a transceiver based on the value. In one embodiment, electronic component is a resistor having a value that identifies the antenna properties. A table may be used to correlate resistor values to different types of antennas or sets of antenna properties. Alternatively, the circuit can be embodied in a microchip that provides a response to a challenge sent by the read mechanism. The response encodes the properties of the antenna. The encoding scheme includes values from the challenge. Alternatively, the response is a code that is indexed into a table of antenna properties. In one embodiment, the antenna is connectorized.
摘要:
A dual band radio is constructed using a primary and secondary transceiver. The primary transceiver is a complete radio that is operational in a stand alone configuration. The secondary transceiver is a not a complete radio and is configured to re-use components such as fine gain control and fine frequency stepping of the primary transceiver to produce operational frequencies of the secondary transceiver. The primary transceiver acts like an intermediate frequency device for the secondary transceiver. Switches are utilized to divert signals to/from the primary transceiver from/to the secondary transceiver. The switches are also configured to act as gain control devices. Antennas are selected using either wideband or narrowband antenna switches that are configured as a diode bridge having high impedance at operational frequencies on control lines that bias the diodes.
摘要:
An antenna switch diversity algorithm, and systems and methods to provide antenna diversity by implementing the algorithm in, for example, an IEEE 802.11a compliant environment, are presented. In accordance with the algorithm, one antenna of at least two antennas is designated as a default antenna at a communications device that sends and receives transmit and receive packets. The default antenna designation is changed depending on long-term and short-term learning processes implemented in, for example, software and hardware. The long-term and short-term learning processes analyze packet transmission and reception results of the antennas. The antenna switch diversity algorithm is applicable to multiple antennas.
摘要:
A system and method are described for reducing data transmission collisions in a shared transmission medium. In one embodiment, transmission priorities are set by means of priority-defining transmissions. In another embodiment, statistically equal access is assured by means of unique transmit start time slot pairs wherein the paired start time slots are substantially equally spaced in time from a center start time slot. In yet another embodiment, data transmission traffic analysis is used to set unique transmission start time slots or to select from pools of start time slots associated with classes of data to be transmitted, thus establishing relative preemption priorities. In still another embodiment, transmission begins in statically assigned start time slots that are subsets of an available array of transmission start time slots.
摘要:
An embodiment of the present invention provides an automatic gain control system for a wireless receiver that quickly differentiates desired in-band signals from high power out-of-band signals that overlap into the target band. The system measures power before and after passing a received signal through a pair of finite impulse response filters that largely restrict the signal's power to that which is in-band. By comparing the in-band energy of the received signal after filtering to the total signal energy prior to filtering, it is possible to determine whether a new in-band signal has arrived. The presence of this new in-band signal is then verified by a multi-threshold comparison of the normalized self-correlation to verify the presence of a new, desired in-band signal.
摘要:
A system for detecting and avoiding interference with radar signals in wireless network devices is described. The receiver circuit of the device receives incoming 5 GHz traffic. Such traffic could comprise both WLAN traffic as well as radar signals from radar systems. The incoming packets are treated as an input event, and are screened to be examined as radar pulses. Radar pulses are identified using the length of the detected event. The radar pulses are examined using frequency domain analysis, and the packet train is examined to find gaps between radar pulses. The periodic nature of the packet is determined using frequency domain and time domain analysis to calculate the period of the pulse train. Particular intervals within the pulse train are analyzed using threshold numbers of periodic pulses within the interval and threshold power levels for the pulses. The calculated period information is used to identify the radar source and screen non-radar traffic.
摘要:
A modified approach to detecting the start frame delimiter (SFD) is disclosed. A receiving system scans a decoded but not yet de-scrambled received signal for a scrambled version of the SFD associated with the preamble format being used. Using this approach, it is not necessary to use any bits intended for use in synchronization to initialize a de-scrambler so as to be able to de-scramble the SFD portion of the preamble for detection. The bits that otherwise would have been dedicated to initializing the de-scrambler may then be used for synchronization, as intended. Detecting fewer than all bits comprising a start frame delimiter is described. Bits not used for SFD detection may be used for other purposes, such as synchronization.
摘要:
A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between god and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss.
摘要:
A system for detecting the level of the noise floor due to circuit noise as seen at the ADC for a wireless receiver. The system measures power after digitizing and filtering, and subtracts off any variable gain used in the analog front end to determine differentially the size of the signal at the antenna. The system further differentially detects the signal size of any incoming signal at the antenna in a similar fashion, and determines its size relative to the measured noise floor. If the level of the circuit noise of the receiver is known absolutely, the absolute signal size of the incoming signal can likewise be determined with this inventive method and system.
摘要:
Method and apparatus to dynamically configure the signal reception selectivity of a plurality of transceivers is described. In one embodiment, a transceiver includes a receiver circuit having two or more filter circuits. Each of the filter circuits is configured to pass RF signals from a different portion of an overall receiver bandwidth. When two or more receivers in proximity to one another are simultaneously operating, the filter circuits of the respective receiver are dynamically configured to different RF frequency passbands to minimize interference and cross talk between receivers and transmitters.