Abstract: According to one embodiment, an apparatus that makes improved routing decisions is provided that includes a receiver, a retriever, a proximity engine, and a transmitter. The receiver may be configured to receive a request from a source. The retriever may be configured to retrieve a plurality of providers capable of servicing the request. The proximity engine may be configured to rank the plurality of providers based on weights indicative of a network distance. The weights may correspond to a first Border Gateway Protocol (BGP) community attribute associated with the source and at least a second BGP community attribute associated with at least one of the providers in the plurality of providers. The transmitter may be configured to transmit the request to the provider in the plurality of providers with the highest ranking.

Abstract: In one embodiment, a first network device may receive a request for an identifier of at least one target to service a client. The first network device may obtain an identifier of each of two or more targets. The first network device may then determine whether to redirect the request. The first network device may redirect the request to a second network device according to a result of the determining step, where the first network device is in a first autonomous system and the second network device is in a second autonomous system.

Abstract: Systems may use explicit ratings from users to construct user to user correlations. This technique may reduce the user-content correlation to a single dimension, i.e., the content that a plurality of users may rate similarly. Embodiments of the present invention may use DHT as an underlying distributed signaling mechanism, but may also make the rating implicit. Furthermore, embodiments of the present invention may construct the user to content correlation based on multi-dimensional metadata related to the content.

Abstract: The invention relates to a novel methodology and apparatus for clock-offset compensation and common-phase offset correction in Frequency Division Multiplexing based wireless local area network (WLAN) environment, such as an Orthogonal Frequency Division Multiplexing (OFDM) environment. A curve fit, such as a threshold-based, least mean squares (LMS) fit of phase of the pilot sub-carriers in each OFDM symbol is used to estimate and counteract the rotation of the data sub-carriers due to residual frequency offset, low frequency phase noise, and clock offset. The invention is particularly well suited to wireless channels with multipath where pilots typically undergo frequency-selective fading. The thresholding LMS is implemented in a hardware-efficient manner, offering cost advantages over a weighted-LMS alternative. Additionally, the invention uses a unique phase-feedback architecture to eliminate the effects of phase wrapping, and avoid the need to refine channel estimates during packet reception.

Abstract: In system of DHT rings that are not filly meshed with each other, flooding of PUT and GET messages is limited by PUTting a content key indicating an actual storage location of content from a content provider only to root DHTs associated with the content provider, and PUTting a secondary key indicating a subset of DHT rings at which content from the content provider might be stored only to DHT rings for which the content provider desires the content to be available. When a DHT receives a GET it first determines from the content key whether it can provide the content and if not, the DHT obtains the subset of DHT rings from the secondary key and forwards the GET of the content key to the corresponding root DHTs.

Abstract: The present invention allows multi-channel communications equipment to detect and eliminate a false interpretation of interference as a valid signal. The solution is based on the observation that the simultaneous arrival of energy on two independent channels is an impossible event. So, when such an event happens, it is a reliable signature of confusing out-of-band energy for a valid signal.

Abstract: Upon a triggering event, a delay chain shifts data out at a higher rate than incoming packets and a processor controls bypassing circuitry to reduce the latency of hardware implementations of, for example, 802.11a OFDM receivers, with long delay chains. The signal processing algorithms used to recover symbol timing need a large number of samples stored in a delay chain, often consisting of pipelined registers. Such a delay chain introduces a large lag between the time samples have been acquired by the data converters and the time they are processed. This delay makes it difficult for higher level network layer implementations to meet the deadlines of 802.11a WLAN protocol. The proposed scheme implements dynamic reduction in the depth of the delay chain once timing recovery has been performed. A multi-step scheme achieves exponential reduction in the number of elements in the delay chain in every step.

Abstract: The invention relates to a novel methodology and apparatus for clock-offset compensation and common-phase offset correction in Frequency Division Multiplexing based wireless local area network (WLAN) environment, such as an Orthogonal Frequency Division Multiplexing (OFDM) environment. A curve fit, such as a threshold-based, least mean squares (LMS) fit of phase of the pilot sub-carriers in each OFDM symbol is used to estimate and counteract the rotation of the data sub-carriers due to residual frequency offset, low frequency phase noise, and clock offset. The invention is particularly well suited to wireless channels with multipath where pilots typically undergo frequency-selective fading. The thresholding LMS is implemented in a hardware-efficient manner, offering cost advantages over a weighted-LMS alternative. Additionally, the invention uses a unique phase-feedback architecture to eliminate the effects of phase wrapping, and avoid the need to refine channel estimates during packet reception.

Abstract: Using a combination of auto-correlation and cross-correlation techniques provides a symbol timing recovery in a Wireless Local Area Network (WLAN) environment that is extremely robust to wireless channel impairments such as noise, multi-path and carrier frequency offset. An auto-correlator provides an estimate for a symbol boundary, and a cross-correlator is subsequently used to more precisely identify the symbol boundary. Peak processing of the cross-correlation results provides further refinement in symbol boundary detection. In receiving a packet conforming to the IEEE 802.11a standard, the method requires a minimum of only three short symbols of the 802.11a short preamble to determine timing, and guarantees timing lock within the duration of the 802.11a short preamble. This method and system can be easily applied to any other preamble based system such as 802.11g and High Performance Radio LAN/2 (HIPERLAN/2).

Abstract: Gain variations during a packet can lead to significant performance degradation in communications systems that use high order quadrature amplitude modulation (QAM). A method and the associated apparatus track such variations in an OFDM system and completely eliminate any performance degradation. Gain estimation and compensation is employed with the use of pilot subcarriers in the payload of an OFDM data packet. Estimated pilot magnitude ratios are averaged, throughout the processing life of a packet, to yield accurate gain estimations. A gain compensation factor is used to adjust data carriers. An exclusion method is also employed to eliminate pilot carriers which contribute to noise.

Abstract: Automatic Gain Control (AGC) system for multi-channel signals attenuates an incoming multi-channel signal by providing a gain. The system further adjusts each individual channel, of the multi-channel signal, by supplying a second gain if needed. The AGC system is designed to ensure a received signal power is at an optimal level for analog to digital conversion or any other form of signal processing. The system also enables elimination of mid-packet gain adjustments.

Abstract: In estimating and compensating impairments of Orthogonal Frequency Division Multiplexing (OFDM) symbols, a first estimation is obtained by evaluating and comparing received training symbols with transmitted training symbols. A second estimation is obtained by evaluating and comparing a first portion of received payload symbols with estimated payload symbols. A final estimation is obtained by combining the first and second estimations. Compensation of a second portion of the payload symbols is obtained by using the final estimation, while compensation of the first portion of the payload symbols is obtained by using the first estimation. The current method and apparatus, ideal for low rate systems, disclosed herein allows for required signal-to-noise ratio (SNR) performance less then 0.2 dB away from the best achievable performance without the introduction of complex or expensive hardware.

Abstract: An efficient coding scheme is disclosed. The coding provides for the separation of immediate data from the instruction stream. A static flow analysis determines the immediate data in the program and assigns it a location for storage in a data table. The flow analysis also generates information directing the processor to the location of the immediate data in the data-order table. When an immediate instruction is encountered during execution, the processor retrieves the immediate data from the data-order table.

Abstract: In a multi-user radio receiver, a method and apparatus for reducing the effects of non-linear distortion due to adjacent channel interference (ACI) includes receiving and processing a multi-user information signal to provide a plurality of multi-user information values and then detecting, from the plurality of multi-user information values, at least a first information value having a signal strength which is relatively high compared with the signal strengths of the other plurality of multi-user information values. The apparatus then utilizes the plurality of multi-user information values, the first information value and a spectral representation of the first information value to generate a plurality of second information values having significantly reduced adjacent channel interference with respect to the first information value. The method and apparatus can thus increase the system capacity by increasing the frequency reuse factor in the a receiver system (e.g.

Abstract: The present invention allows multi-channel communications equipment to detect and eliminate a false interpretation of interference as a valid signal. The solution is based on the observation that the simultaneous arrival of energy on two independent channels is an impossible event. So, when such an event happens, it is a reliable signature of confusing out-of-band energy for a valid signal.

Abstract: Upon a triggering event, a delay chain shifts data out at a higher rate than incoming packets and a processor controls bypassing circuitry to reduce the latency of hardware implementations of, for example, 802.11a OFDM receivers, with long delay chains. The signal processing algorithms used to recover symbol timing need a large number of samples stored in a delay chain, often consisting of pipelined registers. Such a delay chain introduces a large lag between the time samples have been acquired by the data converters and the time they are processed. This delay makes it difficult for higher level network layer implementations to meet the deadlines of 802.11a WLAN protocol. The proposed scheme implements dynamic reduction in the depth of the delay chain once timing recovery has been performed. A multi-step scheme achieves exponential reduction in the number of elements in the delay chain in every step.

Abstract: Using a combination of auto-correlation and cross-correlation techniques provides a symbol timing recovery in a Wireless Local Area Network (WLAN) environment that is extremely robust to wireless channel impairments such as noise, multi-path and carrier frequency offset. An auto-correlator provides an estimate for a symbol boundary, and a cross-correlator is subsequently used to more precisely identify the symbol boundary. Peak processing of the cross-correlation results provides further refinement in symbol boundary detection. In receiving a packet conforming to the IEEE 802.11a standard, the method requires a minimum of only three short symbols of the 802.11a short preamble to determine timing, and guarantees timing lock within the duration of the 802.11a short preamble. This method and system can be easily applied to any other preamble based system such as 802.11g and High Performance Radio LAN/2 (HIPERLAN/2).

Abstract: The invention relates to a novel methodology and apparatus for clock-offset compensation and common-phase offset correction in Frequency Division Multiplixing based wireless local area network (WLAN) environment, such as an Orthogonal Frequency Division Multiplexing (OFDM) environment. A curve fit, such as a threshold-based, least mean squares (LMS) fit of phase of the pilot sub-carriers in each OFDM symbol is used to estimate and counteract the rotation of the data sub-carriers due to residual frequency offset, low frequency phase noise, and clock offset. The invention is particularly well suited to wireless channels with multipath where pilots typically undergo frequency-selective fading. The thresholding LMS is implemented in a hardware-efficient manner, offering cost advantages over a weighted-LMS alternative. Additionally, the invention uses a unique phase-feedback architecture to eliminate the effects of phase wrapping, and avoid the need to refine channel estimates during packet reception.

Abstract: A unified digital front end filtering circuit is described for IEEE 802.11g protocol compliant systems. The front end uses polyphase rate conversion filters cascaded with channel extraction and pulse shaping filters to accommodate the different sampling rate requirements for orthogonal frequency division multiplexing (OFDM) and direct sequence spread spectrum (DSSS) modulation, which have to be supported simultaneously, without using separate analog front ends.

Abstract: To support local number portability and service portability in a telephone network, a method and apparatus handle subscription and administrative service requests in a local service management system to maintain records at a service control point. The subscription requests include create, modify, and delete requests of records in the service control point. The administrative service requests include Numbering Plan Area (NPA) code split, mass change, and query and resend requests. The records at the service control point are accessible by switches via respective signal transfer points to determine the network addresses of the switches handling services and calls corresponding to a particular telephone number.