Abstract: An apparatus and method is provided for measuring medium activity patterns in wireless networks and deriving information about the radio environment from the measured medium activity/patterns. This invention is three-fold. First, it defines what to measure, including medium idle/busy patterns based on power detection, medium idle/busy pattern based on preamble detection, and medium idle/busy pattern based on virtual sensing. Second, it provides a mechanism for communicating the measurement request and report, as illustration for the case of IEEE 802.11. And last, it defines the information that can be derived given these measurements as discovery of: non-802 devices, 802.11e systems, 802.11e contention-based medium access priorities, 802.11e controlled medium access usage, 802.11b/g existence, and hidden stations.

Abstract: Under the present invention, a wireless component such as an access point or a mobile device is configured to manage the buffering of newly transmitted TCP packets. Specifically, the wireless component can receive both forwarded TCP packets and newly transmitted TCP packets. If a set of newly transmitted TCP packets is received out of order(i.e., before a set of previously transmitted TCP packets that must be forwarded), one out of order (newly transmitted) TCP packet will be passed for each of a quantity of tokens present on the wirelesss component. Each out of order TCP packet that is not passed will be buffered. Once a previously requested forwarded TCP packet is received and passed, the quantity of tokens is restiored to a predetermined quantity, and a commensurate number of buffered TCP packets can be passed.

Abstract: An apparatus and method are provided for power management in an Independent Basic Service Set (IBSS) Wireless Local Area Network (WLAN) based on adjusting ATIM window size dynamically. In the present invention, each STA uses the gap between the last overheard Ad-hoc traffic indication message ATIM frame transmission and the end of the ATIM window to determine whether to increase or decrease the size of its ATIM window. Each STA of an IBSS competes to send its Beacon containing the size of its ATIM window and the window size of the winner is adopted by all STAs of the IBSS.

Abstract: Under the present invention, a method and system for improved handoff of a mobile device between wireless subnetworks is provided. Specifically, under the present invention, a mobile device will directly associate with a new access point of a new wireless subnetwork (layer 2 handoff) before associating with a agent of the new subnetwork (layer 3 handoff). Once the association with the new access point is complete, a forwarding request will be sent from the new access point to the old access point of the wireless subnetwork wit which the mobile device w as previously associated. The forwarding request causes all data packets intended for the mobile device that are received by the old access point to be forwarded to the new access point. Then, once the mobile device has the completed its association with the agent of the new wireless subnetwork, the mobile device will receive data packets directly through the new subnetwork.

Abstract: An apparatus and method are provided by the present invention for power management in an Independent Basic Service Set Wireless Local Area Network (WLAN). The present invention uses explicit booking by wireless stations and implicit booking by overhearing booking and data frame transmission conversations by the wireless stations to achieve higher throughput thereby optimizing power use in an IBSS WLAN for a given Ad-hoc Traffic Indication Message (ATIM) window size.

Abstract: A wireless local area network (WLAN) includes at least one hybrid coordinator (HC) and at least one Quality of Service Station (QSTA). The HC transmits a schedule frame element (SEF). The WLAN also includes a clocking mechanism that sets a substantially absolute start time of a service interval. A method of synchronizing the HC and the QSTA includes transmitting a schedule element frame (SEF), and setting a substantially absolute start-time of a service interval, and a first transmitted frame element.

Abstract: The present invention is directed to reduced B-frame decoding. According to the present invention, the number of transform coefficients in B-frames are reduced to produce reduced B-frames. Also, inverse scanning and inverse quantization is performed on the reduced B-frames. Further, an inverse transform is performed on the reduced B-frames. In one embodiment of the present invention, the reduced B-frames are produced by identifying blocks associated with the B-frames and selecting transform coefficients included in a predetermined area of the identified blocks.

Abstract: Data compressed according to a lossy DCT-based algorithm, such as the MPEG or MPEG2 algorithms, is decompressed according to a dynamically-selected set of DCT coefficients, with unused coefficients masked out. A macroblock of the data exhibiting little motion is decompressed with a small subset of DCT coefficients, while a macroblock exhibiting more motion is decompressed using a larger subset of DCT coefficients up the full set of DCT coefficients. Average computational complexity is thus kept low, enabling the use of inexpensive equipment, while degradation is minimized.

Abstract: Disclosed is a system and method for performing a fast channel scan so as to minimize the communication disruption period (10) which occurs during a handoff of a mobile station (STA) (20-23) in a wireless local area network (WLAN) (100). Each mobile station (STA) includes an associated nearest-neighbor table identifying nearest-neighbor APs (14-16) in the network to the AP with which the STA is currently associated. When a STA (20-23) performs a handoff, its nearest-neighbor table is used to perform a prioritized search of those channels of operation included in the table belonging to nearest-neighbor APs (14-16). In this manner, by prioritizing the search to first search the channels of operation belonging to nearest-neighbor APs (14-16), there is a greater likelihood of locating a candidate ap (14-16) to form an association with in less time as compared with the prior art search method of blindly searching each and every operating channel in the network.

Abstract: An apparatus and method is provided for power management in an Independent Basic Service Set (IBSS) Wireless Local Area Network (WLAN) that replaces the Ad-hoc Traffic Indication Message (ATIM) and its associated control logic, with a protocol comprising a variable length Data Alert frame transmission period or Data Alert window that accommodates the traffic in the IBSS and is followed by a data frame transmission period, a special End of Alert frame, a special LIFS for the End of Alert frame and new control logic. The End of Alert frame has a lower priority in a contention for a medium with a Data Alert frame, i.e., the Data Alert frame has the equivalent of a higher priority, thereby maximizing the number of Data Alerts sent during any Data Alert window. This approach to power management achieves optimal allocation of time used to send Data Alert frame and data frame thus minimizes power consumption by all wireless stations of the IBSS.

Abstract: Data compressed according to a lossy DCT-based algorithm, such as the MPEG or MPEG2 algorithms, is decompressed according to a dynamically-selected set of DCT coefficients, with unused coefficients masked out. A macroblock of the data exhibiting little motion is decompressed with a small subset of DCT coefficients, while a macroblock exhibiting more motion is decompressed using a larger subset of DCT coefficients up the full set of DCT coefficients. Average computational complexity is thus kept low, enabling the use of inexpensive equipment, while degradation is minimized.

Abstract: A system and method that reduces computational complexity of a decoder by identifying a skippable region in an overlaid area. The invention provides a system for processing encoded video data, comprising: an analysis system that determines if a current video frame having an overlaid area acts as a reference for future video frames; and a system for identifying a skippable region in the overlaid area. The invention may also include a system for identifying a portion of the overlaid area as the skippable based on analysis of motion vectors or motion vector ranges.

Abstract: A method and system of reducing the computation load of an MPEG decoder by changing the encoding algorithms in a video-processing system are provided. During an encoding mode, a stream of data blocks is received and at least one motion vector and one motion compensation prediction value for each macro-block are generated. The prediction value is transformed into a set of DCT coefficients. Prior to the quantizing step, the set of DCT coefficients are modified according to predetermined criteria. To this end, the total energy level of the DCT coefficients excluding the lowest 2×2 DCT coefficients is computed, and last column and last row of the DCT coefficients is discarded alternatively until the total energy level of the DCT coefficients reaches a predetermined energy level. Therafter, the discarded column or row is assigned to a predetermined value.

Abstract: A video processing system comprising: a decoder having a complexity reduction system; and a post-processing system for processing an output of the decoder, wherein the post-processing system includes a filter for intentionally blurring a set of frames in a group of pictures (GOP) to achieve a smooth visual transition between frames.

Abstract: A system and method for scaling an MPEG-2 video decoder subject to a resource constraint. A decoder system is provided for decoding compressed video data arranged in a group of pictures, wherein the group of pictures include I pictures, P pictures and B pictures. The system comprises a processing path for decoding an error residual associated with the group of pictures, and a filtering system for preventing the error residual associated with B pictures from being decoded by the processing path. The decoder system may further comprise a system for selectively enabling the filtering system for B pictures having a DC coefficient that is below a predetermined threshold.

Abstract: The present invention can complement and benefit virtually any method utilizing motion compensation to decode an inputted digital video data stream by determining a likely local nature of reference frame data area in the video data stream and then applying proper interpolation to the reference frame data area according to the determined likely local nature of the reference frame data area. The present invention can also complement and benefit virtually any decoding system utilizing motion compensation to decode an inputted digital video data stream by providing a motion compensation predictor that is adapted to determine a likely local nature of a reference frame data area in the video data stream and then apply proper interpolation to the reference frame data area according to the determined likely local nature of the reference frame data area.

Abstract: A method and system of regulating the computation load of an MPEG decoder in a video processing system are provided. The video processing system processes the header information of a compressed video data stream including a plurality of macroblocks with a motion vector associated therewith. Then, the computation load of each functional block of the MPEG decoder is adjusted according to predetermined criteria; thus, substantial computational overhead is desirably avoided.

Abstract: The present invention is directed to MPEG decoding with embedded resizing that includes detecting and interpolating moving areas in interlaced video in order to eliminate irregularities in the output video. According to the present invention, the decoding includes down scaling a motion vector. Also, detecting a moving area in an interlaced video reference frame and modifying the reduced resolution motion vector. Further, retrieving pixel values from the interlaced video reference frame according to the modified motion vector.

Abstract: A system and method for filtering interlaced video in the DCT domain. The invention implements an even length symmetric filter necessary for filtering the bottom field of pixel data using the steps of: decomposing the even symmetric spatial filter design into two identical odd length symmetric filter designs have a one pixel phase difference therebetween; creating a discrete cosine transform (DCT) filter that corresponds to the odd length symmetric filter designs; filtering the field of interlaced video data in the DCT domain using DCT filter to create a set of filtered DCT data; converting the set of filtered DCT data into a set of spatial domain data; and filtering the spatial domain data with a [1,1] filter.

Abstract: In a wireless local area network (WLAN), the present invention provides a system and method for identifying traffic suffering from bad link quality and dynamically adjusting channel access to restrict the effect of this bad link quality. The dynamic adjustment to channel access is accomplished by lowering or raising the limit on the number of packets that can be transmitted between an AP and the wireless station over the a link as determined by the link quality. The link quality is determined by tracking the number of successive packet transmission successes and errors.