Abstract: An apparatus and method for operating a Multiple Input Multiple Output (MIMO)-capable subscriber node are disclosed. In one embodiment, an apparatus includes a MIMO-capable physical layer transceiver and a Medium Access Control (MAC) layer block that measures a received transmission to determine channel conditions. Upon receiving a transmission wherein said channel conditions meet specified conditions, the MAC layer block transmits a message to an access point indicating that the apparatus wants to switch between a non-MIMO mode and a MIMO mode, and upon receiving an acknowledgement, the MAC layer block switches between the non-MIMO mode and the MIMO mode. An apparatus for operating an access node is also disclosed.

Abstract: An apparatus and method for operating a Multiple Input Multiple Output (MIMO)-capable subscriber node are disclosed. In one embodiment, an apparatus includes a MIMO-capable physical layer transceiver and a Medium Access Control (MAC) layer block that measures a received transmission to determine channel conditions. Upon receiving a transmission wherein said channel conditions meet specified conditions, the MAC layer block transmits a message to an access point indicating that the apparatus wants to switch between a non-MIMO mode and a MIMO mode, and upon receiving an acknowledgement, the MAC layer block switches between the non-MIMO mode and the MIMO mode. An apparatus for operating an access node is also disclosed.

Abstract: Systems and methods for improving throughput in point-to-point wireless communication links are provided. In one particular implementation, a media access control (MAC) layer of the IEEE 802.11 standard is enhanced for use in point-to-point links to take advantage of the limited number of nodes participating in the link. In one embodiment, a master/slave type protocol provides contention free operation between two wireless nodes. Multiple priority levels and voice traffic may be accommodated with guaranteed Quality of Service.

Abstract: An apparatus and method for operating a Multiple Input Multiple Output (MIMO)-capable subscriber node are disclosed. In one embodiment, an apparatus includes a MIMO-capable physical layer transceiver and a Medium Access Control (MAC) layer block that measures a received transmission to determine channel conditions. Upon receiving a transmission wherein said channel conditions meet specified conditions, the MAC layer block requests an access point for permission to switch between a non-MIMO mode and a MIMO mode, and upon receiving permission, the MAC layer block switches between the non-MIMO mode and the MIMO mode. An apparatus for operating an access node is also disclosed.

Abstract: Systems and methods for improving throughput in point-to-point wireless communication links are provided. In one particular implementation, a media access control (MAC) layer of the IEEE 802.11 standard is enhanced for use in point-to-point links to take advantage of the limited number of nodes participating in the link. In one embodiment, a master/slave type protocol provides contention free operation between two wireless nodes. Multiple priority levels and voice traffic may be accommodated with guaranteed Quality of Service.

Abstract: A method, apparatus, and carrier medium for determining channel state information (CSI) in an OFDM radio receiver. The receiver is for receiving packets of OFDM data as a result of OFDM data being transmitted. The method includes forming an estimate of the channels of the subcarriers for received OFDM data to provide frequency responses of the channels of the subcarriers, and forming a measure of quality (“channel state information,” “CSI”) for the channels of the subcarriers based on the relative strength of the frequency responses. The forming of the CSI does not require estimating the relative amount of noise or interference in each channel. The formed CSI is used in demodulating and decoding received OFDM data.

Abstract: The MAC layer of a wireless communication standard is modified to facilitate MIMO (multiple input multiple output) processing and thereby increase capacity and/or spectral efficiency. In one implementation, the IEEE 802.11a standard is modified in this way. A contention free period (CFP) is divided between MIMO communications and non-MIMO communications. An access point may maintain a list of nodes operating in MIMO mode and nodes operating in non-MIMO mode.

Abstract: Systems and methods for retransmitting unsuccessfully transmitted data across a communication link. The retransmission mechanism may be applied to point to multipoint networks including wireless networks. Each packet is encapsulated in an ARQ frame and assigned a sequence number for the purpose of coordinating acknowledgments and retransmissions. Information as to which packets require retransmission is communicated in the form of a bitmap where each bit indicates an acknowledgment status for a given packet. Any missing packets in the received sequence are assumed to require retransmission.

Abstract: Methods for provisioning optical communications networks employing wavelength division multiplexing (WDM) technology provide for routing and wave-length assignment of a set of connection requests. Avoiding many of the pitfalls of exactly optimum solutions, the present heuristic methods provide much shorter execution times while providing near-optimum performance. Adaptations of the basic solutions provide design of restorable networks capable of handling a specified set of failures. This approach advantageously is based on considering all failures simultaneously, and performs better than solutions in which independent designs are developed for each failure. Networks designed using these methods store configuration information for primary network configurations and for one or more restoration networks.

Abstract: The present invention is a restoration scheme for an ad-hoc ATM LAN wherein ATM cells are transported over a wireless point-to-point link. A method for restoring communications in the ATM network includes the steps of: generating a failure message indicative of a failure of a network element, the failure message including an identification of said network element and a predetermined VPI/VCI reserved for failure reporting; communicating the failure message to all said switching nodes in said network; and referencing updated routing tables at said switching nodes, wherein said network element indicated in said failure message is eliminated from routes in said network. Each of the switching nodes is included in a network tree spanning all said switching nodes in the network, wherein each of the switching nodes is included as a root in a specific network tree, each said network tree having a tree identification, the failure message further including a tree identification field containing the tree identification.

Abstract: A facility is provided for establishing a relatively low-speed path from a user desiring to access the well-known Internet and establishing a high-speed path from the Internet to the user so that the data speed accommodates both the user's requests and a response from an Internet web/host site. Moreover, a user may be mobile, in which case the low-speed path is a conventional wireless path. In most cases, a predetermined spectrum of frequencies, such as one or more television channels, is used as the high-speed path from Internet.

Abstract: A telecommunications system capable of transmitting an N byte packet over a common communications channel by: temporally dividing the common communications channel into time slots that have a duration equal to ##EQU1## seconds, where i is a natural number greater than one, C is a constant and R is the transmission rate of the common communications channel in bytes per second; splitting the N byte packet into i p-packets; preparing an M byte training sequence; and transmitting the M byte training sequence and the p-packets over the common communications channel in consecutive time slots.

Abstract: The present invention is a signaling and control architecture for establishing a connection between mobile users in a wireless ATM LAN. The ATM LAN includes a plurality of portable base station (PBS) switching nodes coupled together to enable communication between said nodes, wherein the nodes are configurable in an arbitrary topology to form an ad-hoc network. The present invention includes network management techniques for configuration of data tables used for connection control. Mobility management techniques are disclosed to handle mobile sign-ons and idle handoffs, locate mobile users during connection and setup and perform handoffs when a mobile is actively involved in a connection. Connection control procedures are also included for setting up and releasing connections on demand.

Abstract: Increased numbers of multipath transmission errors, that are detected by the performance of cyclic redundancy checking (CRC) over time and frequency on the words of a multitone transmission block that include mapped information bits, are correctable by forward error control as a result of the iterative performance of CRC over frequency on subblocks of the transmission block using retransmitted parity checking bits. A continuous record is maintained of the frequency channels that are detected as experiencing transmission errors in order to maximize the rate of data bit transmission on frequency channels that are likely to experience a reduced number of transmission errors.

Abstract: The present invention is a reliable data link layer protocol to transport ATM cells over a wireless point-to-point link. The protocol ensures that the cells are transported reliably by use of a sliding window transport mechanism with selective repeat automatic repeat request (ARQ) and forward error correction (FEC). The protocol minimizes ATM header overhead by means of header compression and provides per-cell FEC whose size can be changed adaptively. The protocol also provides parity cells for recovery from errors that cannot be corrected using the per-cell FEC field. The number of these cells as well as the size of a window or frame can also be adaptively changed. In addition, the window can be terminated to request an immediate acknowledgment.

Abstract: A navigation system for an automotive vehicle designed to display a road map image around the vehicle in correlation with the current position of the automotive vehicle. The navigation system is adapted to determine a best navigation route to a selected destination on the basis on the approximated time necessary to travel such a navigation route in correspondence to its travel length and speed rate.

Abstract: A forward error correction system adaptively changes the number of parity bits, bytes or packets transmitted to a receiver, based on previous error patterns experienced recently in the reception of original and parity bits, bytes or packets by that receiver.

Abstract: A wireless communications system is arranged to provide data communications services, including error recovery, between at least one wireless end-user device and at least one one base station. The wireless end user device(s) receives(s) from the base station(s) unsolicited messages indicative of the status of data packets received by the base station(s). The wireless end-user device(s) transmit acknowledgement and request for retransmission messages only upon request, or when all the packets within a block of such packets have been received.

Abstract: The present invention is a quantization-level-sampling (QLS) modem which includes means for separately equalizing each loop of an end-to-end digital telephone system network connection by employing a plurality of transmitter filters and a plurality of receiver filters in such a way that, in the direction of transmission from modem to central office, the voltage samples seen by the coder/decoder stations are equivalent to the network quantization levels transmitted by the modem, and in the direction of transmission from central office to modem, the voltage samples seen by the modem are equivalent to the network quantization levels encoded by the coder/decoder stations. The invention also includes a QLS modem communications system which includes the aforesaid digital telephone system network and a plurality of QLS modems. In preferred embodiments, an adaptation service unit within the telephone system network assists in the determination of the settings of the transmitter and receiver filters.

Abstract: A modem that operates reliably at a symbol rate that corresponds to twice its bandwidth even when it is coupled to a receiving A/D converter that operates under control of a clock is realized by synchronizing the modem's operation to the A/D's clock. The superior operation of this modem advantageously extends to A/D clock frequencies beyond the frequency of twice the modem's bandwidth. To minimize quantization noise, the modem's output is conditioned to minimize intersymbol interference by adjusting the modem's output to the A/D converter's sampling times and slicing levels. When the A/D's clock is higher than twice the bandwidth of the modem's output signal, some intersymbol interference cannot be avoided. In accordance with this invention, the position and value of this interference is computed at the receiver and subtracted from the received signal.