Abstract: Synchronization within a common communication channel having designated transmission time slots for various devices of a computer network is maintained by allowing transmissions within the channel outside of a network device's designated time slot when a clear channel assessment indicates that a previous time slot is not being utilized by its associated device and/or upon receipt of an indication of the end of a transmission of another device in the network. The clear channel assessment preferably takes into account the device's designated transmission time slot within the communication channel with respect to those of other network devices and may be a time period that is the product of a predetermined clear channel waiting time and a numerical representation of the device's designated transmission time slot within the communication channel with respect to those of other network devices. The clear channel waiting time itself may be specified by a network master device as part of a network connection process.

Abstract: A medium access control (MAC) layer for a node of a wireless local area network, which may be used in embedded, host and stand-alone applications, includes a hardware layer and a software layer. The hardware layer is configured to perform time-critical tasks and the software layer is configured to perform non-time critical tasks. The software layer includes multiple modules, such as one or more of a host communication agent, a bridging layer, a network management support module, a SBM-to-TAME conversion module, and a rate estimation module. Further, the software layer acts as the source of and the destination of MAC Service Data Units and is configured as a hierarchical structure in which functional unit blocks for associated elements of the hardware layer communicate with an application layer through respective device drivers and managers. Device drivers and managers communicate through a device manager layer.

Abstract: A networking protocol includes definitions of quality of service enhancements to provide reliable multimedia data stream connections in wireless computer networks. These enhancements may be implemented as extensions to packet headers, such as a multimedia control field made up of various sub fields.

Abstract: Transmissions within a communication channel utilized by devices of a computer network that are outside of a device's designated time slot are accommodated through the use of a clear channel assessment time. The clear channel assessment time takes into account the device's designated transmission time slot within the communication channel with respect to those of other network devices. Thus, the clear channel assessment time may be a time period that is the product of a predetermined clear channel waiting time and a numerical representation of the difference between the device's designated transmission time slot within the communication channel and that of another network device that completed a preceding transmission.

Abstract: A communication protocol includes a hierarchical arrangement of time slots within a communication channel for transmission and reception of isochronous data (e.g., video, audio, etc.) between components of a computer network. One of the time slots may include a window for transmission of keyboard and/or cursor control data from a client unit to a server, for example as a series of past and present keyboard and/or cursor control entries, with these entries being accompanied by a counter value indicative of the number of new entries since a previous transmission. Audio rate control information may also be transmitted from the client unit to the server during the reverse time slot and may be used by the server to determine the amount of audio information to be transmitted to the client unit in a subsequent forward time slot transmission period. The audio rate control information is determined according to the amount of stored audio information at the client unit.

Abstract: A packet header for use in information packets transmitted within a computer network includes a protocol extension field that indicates changes of field values and/or lengths within the header. In one embodiment, the protocol extension field includes two bits. The value of the protocol extension field indicates whether or not the packet header has been altered: 00 indicates no alterations, 01 or 10 indicate a predetermined change in the content and/or length of the header, and 11 indicates dynamic negotiation of the field values and/or size. Such packets may be used in a communication protocol for the computer network.

Abstract: A scheme for wireless local area networks provides multimedia extensions for high rate applications. Some of the main extensions provided are the following: The MAC header is extended to include the components for multimedia support. The network topology extensions include tighter definition of the PC, peer-peer connections during CFP, alternate PC and proxy PC. The Quality of Service (QoS) related extensions include the simplifying the operation during CFP, support of streams, stream priority, synchronization of TDM transmissions by devices during CFP, dynamic bandwidth management, channel protection using error control coding and negotiable retransmission parameters. By dynamically negotiating for the priority, bandwidth and the retransmission parameters for each stream separately, the latency control is achieved. There are also proposed extensions to the operation of DCF-only stations in order to better their inter-operation with multimedia capable devices.

Abstract: A scheme for sharing a channel during a contention free period of communications between two or more basic service sets (BSSs) including network components in an overlapping region of a wireless computer network. These network components in the overlapping region may be configured to communicate in contention free periods only. Such bandwidth sharing may then include transmitting within each BSS exclusively during an allocated period of time. Each BSS may include one point coordinator network component and all other network components in the BSS then inform the point coordinator of channel conditions including degradation, and the number of packets received from other BSSs.

Abstract: Communications within a computer network may be controlled by determining that conditions within a first communication channel communicatively coupling components of the computer network are becoming unacceptable for continued utilization of the communication channel and then switching communications within the computer network to a second communication channel. Interference conditions therein preferably being less severe than interference conditions within the first communication channel. The switching may initiated by one of the network components and generally includes placing communications within the first communication channel in a standby condition while searching for an available communication channel. This may be accomplished by instructing the components of the computer network to remain quiet while one of the components searches for an available communication channel, for example by tuning an associated radio to listen in the second communication channel.

Abstract: A communication channel is controlled so as to dynamically accommodate network client requests for access thereto. The communication channel may be supported on a wireless link, such as a spread spectrum wireless link, and client requests for access thereto may be dynamically accommodated by allocating time slots for client transmissions on the wireless link. Providing a quiet time slot within which clients may request access to the communication channel may accommodate various client requests for access to the communication channel. These quiet slots may exist with other forward and reverse time slots which are superimposed on the communication channel, each forward and reverse time slot including one or more data frames. The forward and reverse time slots are preferably fixed, but negotiable, time periods. Each of the data frames may include a plurality of data packets, each of the data packets being variable in length.

Abstract: Within a computer network, a first one of a number of clients may be a consumer of information included within one or more data streams transmitted between a server and one or more others of the clients. However, each of the clients are also communicatively coupled to the server via a command channel independent of these data streams. In some cases, the first client receives the information as the data streams are transmitted from the server to the other clients, while in other cases the first client receives the information as it is being transmitted from the other clients to the server. In addition to the data streams, the first client may exchange additional information with the server. The data streams may be transmitted on a wireless communication link communicatively coupling the server and the clients. However, the first client may receive the information via a communication path separate from the wireless communication link.

Abstract: Data is transmitted over a computer network from a source network component to one or more destination network components. Thereafter, one or more acknowledgements are transmitted from one of the destination network components to the source network component; and different data, which may include retransmissions, from the previously transmitted data is transmitted from the source network component to the one or more destination network components. A negative acknowledgement message from the destination network component may be transmitted to the source network component upon a failure to receive one or more of the transmitted data packets, the negative acknowledgment including packet identifications of said one or more data packets. Then data packets identified by the identifications received in a negative acknowledgement may be retransmitted before transmitting other packets. The negative acknowledgements thus indicate failed receipt of data. Positive acknowledgements indicate successful receipt of data.

Abstract: Processing digital information made up of a plurality of n-bit samples is performed by raising each n-bit value to an x-bit value, x being greater than n. The x-bit values represent mid-band values, wherein in this context a band includes a sequential set of x-bit values having n most significant bits in common and a mid-band value is then an x-bit value approximately centered between the lowest and highest x-bit values of a band including that mid-band value. In some embodiments, the digital information may comprise video information. Thus, the process may be applied prior to converting the video information from a first color space (e.g., a red-green-blue (R-G-B) color space) to a second color space (e.g., a luminance-chrominance (Y-Cr-Cb) color space). For a particular embodiment, n may be equal to five or six, and x may be equal to eight, however, in general n may be variable amongst different ones of the samples.

Abstract: Bandwidth within a common wireless communication channel used by a number of independent computer networks is allocated by assigning a portion of the total bandwidth of the common wireless communication channel to intra-network communications in each of the independent computer networks. This bandwidth allocation scheme may, from time to time, involve revising existing bandwidth allocations for one or more of the independent computer networks, for example when new networks or new clients in existing networks request bandwidth within the channel. The intra-network communications may occur within a slotted link structure that includes transmission times for master and client devices of the respective network. These transmission times are preferably arranged within a hierarchy that includes transmission times for master and client devices of other networks that share the wireless communication channel.

Abstract: A network is configured so as to allow access by a client device for a limited period of time. During this period of time, the client device may have access to designated network resources. In some cases, the network may be so configured on-the-fly; that is, it may be configured to allow access by the client device in response to an installation request transmitted by the client device to a network master device. Such an installation request should include a unique identifier associated with the client device. This unique identifier may be broadcast by the client device without a prompt by the network master device. The use of a unique identifier allows for recognizing the guest client and further facilitates updating a client table wherein information regarding the available bandwidth for the guest client device may be stored. Upon expiration of the period of time, the guest client may be automatically uninstalling from the network.

Abstract: Bandwidth within a communication channel of a computer network is dynamically allocated according to bandwidth requests of devices within the computer network. Such requests may include releases of excess bandwidth in addition to requests for additional bandwidth. In some cases, the communication channel may be a wireless, spread spectrum communication channel. In general, the bandwidth may be dynamically allocated according to priorities of the requests. For example, the requests may be arranged such that those associated with isochronous transmissions within the computer network are accorded the highest priority. A table of such bandwidth allocations may be maintained (e.g., by a network master device) so as to account for bandwidth utilization within the network. Such a table may include bandwidth allocations for the various information streams according to their varying priorities.

Abstract: A network node is configured control operations in a wireless computer network and to automatically hand over network master operations to an alternate network master device upon detecting an operational failure of the network node. In a further embodiment, in response to detecting at a network node of a wireless computer network an impending operational failure of the network node, the node automatically negotiates the hand over of network control responsibilities for the wireless computer network to an alternate network master. Such network control responsibilities may include bandwidth allocation among network clients within the wireless computer network. In still another embodiment, in response to detecting at a node of a wireless computer network (e.g., utilizing a half-duplex communication link) the absence of a master network node, the node will automatically configure itself as an alternate network master.

Abstract: The quality of digital images recovered from compressed data in an inter-frame redundancy-removing scheme is enhanced using a self-adaptive feedback scheme in an image compression/decompression system so as to include means for the compensation of the distortion component from prior frame compression in subsequent difference frame compression. Each transmitted frame is stored after a full compress/decompress cycle, and difference data (which includes the inverse of the distortion component from compression of the transmitted frame) representing the difference between the stored frame and the incoming new frame is transmitted. Consequently, the quality of static regions in the recovered images may be improved with each subsequent iteration by taking the distortion component in the prior frame into consideration along with the inter-frame motion information. The feedback loop thus forms a self-adaptive iterative cycle.

Abstract: The quality of digital images recovered from compressed data in an inter-frame redundancy-removing scheme is enhanced using a self-adaptive feedback scheme in an image compression/decompression system so as to include means for the compensation of the distortion component from prior frame compression in subsequent difference frame compression. Each transmitted frame is stored after a full compress/decompress cycle, and difference data (which includes the inverse of the distortion component from compression of the transmitted frame) representing the difference between the stored frame and the incoming new frame is transmitted. Consequently, the quality of static regions in the recovered images may be improved with each subsequent iteration by taking the distortion component in the prior frame into consideration along with the inter-frame motion information. The feedback loop thus forms a self-adaptive iterative cycle.

Abstract: The quality of digital images recovered from compressed data in an inter-frame redundancy-removing scheme is enhanced using a self-adaptive feedback scheme in an image compression/decompression system so as to include means for the compensation of the distortion component from prior frame compression in subsequent difference frame compression. Each transmitted frame is stored after a full compress/decompress cycle, and difference data (which includes the inverse of the distortion component from compression of the transmitted frame) representing the difference between the stored frame and the incoming new frame is transmitted. Consequently, the quality of static regions in the recovered images may be improved with each subsequent iteration by taking the distortion component in the prior frame into consideration along with the inter-frame motion information. The feedback loop thus forms a self-adaptive iterative cycle.