Cisco Technology, Inc.

Com21, Inc.

Ali Raissinia

Gregory G Raleigh

Vincent Knowles Jones, Iv

Michael A Pollack

Vincent K Jones

David P Bokaie

Joseph Middleton

Derek Gerlach

Mark E Laubach

Kenneth Gorman

Paul Baran

Sanford L Helton

An automatic retransmission system offering good latency and overhead characteristics combined with programmable tradeoffs among overhead, latency, and error performance. ARQ (Automatic Repeat reQuest) blocks present at both ends of a link coordinate to automatically attempt to re-send data if that data was not received properly the first time it was sent. Re-transmission from the transmitter (transmitter) is requested by the receiver (Receiver) via a highly reliable 'Repeat Request' (RR) mechanism. This RR scheme carries sufficient information back to the transmitter for it to determine which previous transmissions need to be re-sent.

ARQ for point to point links

Systems and methods for efficiently transmitting power level information in a point to multipoint wireless system. Multiple subscriber units may transmit indications of their power level within a shared burst where one or more subchannels are allocated to each subscriber unit. The burst holding the power level information may be understood by the MAC layer to be a data burst. In this way, a wireline MAC protocol may be applied to wireless applications.

Realtime power control in OFDM systems

Systems and methods are provided for transferring physical layer control information from a central access point to individual subscriber units while maintaining transparency to higher layers. Adaptation of wireline MAC protocols to wireless applications is greatly facilitated. Subscriber unit power level may be controlled from the central access point.

Communication of physical layer control parameters

Systems and methods for controlling subscriber unit power level using power measurements made on access request transmissions. Since a subscriber unit access request typically precedes a subscriber unit data transmission by a relatively short period of time, the data transmission power level will then be based on a recent power measurement. The access request may also trigger a sequence of power control steps including the transmission of special upstream power measurement transmissions which can be used as the basis for even more accurate power control. These power control features are particularly useful in fading environments such as found in a wireless system.

Optimal use of request access TDMA slots for automatic level control

Improved adjustment of transmission power in a communication system is provided. In one embodiment, in a point to multipoint communication system, transmission power of a subscriber unit is controlled based on power measurements made at a central access point. Power measurement information based on transmissions occurring at irregular intervals may be combined in a beneficial manner to control transmission output power. In one embodiment, a power regulation process determines a series of difference values indicating the differences between desired received power level at the central access point and measured received power level. A smoothing process is applied to the difference values. One or more parameters of the smoothing process vary with elapsed time since a last available power measurement.

Power regulation using multi-loop control

An automatic retransmission system offering good latency and overhead characteristics combined with programmable tradeoffs among overhead, latency, and error performance. ARQ (Automatic Repeat reQuest) blocks present at both ends of a link coordinate to automatically attempt to re-send data if that data was not received properly the first time it was sent. Re-transmission from the transmitter (transmitter) is requested by the receiver (Receiver) via a highly reliable &ldquo;Repeat Request&rdquo; (RR) mechanism. This RR scheme carries sufficient information back to the transmitter for it to determine which previous transmissions need to be re-sent.

Systems and methods for employing digital two-way cable MAC protocols for multi-user wireless communication systems. In one embodiment, a physical layer TDMA framing structure is provided to complement the MAC layer framing. A single MAC layer frame is divided into multiple physical layer frames. The physical layer frames are divided among frames dedicated to transporting data between MAC layer entities and frames dedicated to transporting physical layer control information. Constant delay in transmission through the physical layer is preserved.

Wireless power control in conjunction with a wireline MAC protocol

Systems and methods for providing enhanced subscriber unit power control in a point to multipoint communication system are provided. A central access point may send unsolicited grants of transmission time to individual subscriber units. The subscriber units use the granted transmission time to transmit upstream to the central access point for the purpose of having their output power level measured and regulated. By issuing the unsolicited grants sufficiently frequently, the central access point may maintain optimal subscriber unit transmitter power level. The power control features are particularly useful in fading environments such as found in a wireless system, especially when subscriber units do not transmit data upstream sufficiently frequently for power control to be based on measured power of data transmissions.

Polling for transmission power control

A two-way hybrid fiber-coax cable networks offering high-speed broadband communications delivered via a cable modem service. Bi-directional transmissions of packets between the head-end controller (Cable Modem Terminal System) and cable modems (subscriber terminal units) is accomplished using a cable television Media Access Control (MAC) protocol. In Hybrid Fiber-Coax (HFC) networks, the invention provides a Reverse Path Multiplexing (RPM) function permitting the coupling of a large number of return path (plant) RF ports (return ports) to be coupled to a receiver card in the CMTS. One aspect of this invention is that one or more upstream traffic schedulers reside within the CMTS equipment with the responsibility of scheduling the upstream transmissions from cable modems. The cable modems are distributed across many return ports. The data from each cable modem must be successfully received by the head-end controller without being compromised by the effects of noise funneling. The knowledge of when a cable modem will transmit is used to open an RF switch in the RPM.

Reverse path multiplexer for use in high speed data transmissions

A method for enhancing the functionalities of a subscriber terminal unit (STU) or ADSL terminal unit (ATU) through the use of different types of application interface modules (AIMs). This is accomplished by incorporating a slot in the STU/ATU through which a detachable AIM can be inserted and electrically coupled to the STU/ATU. The STU/ATU has circuitry for determining which particular type of AIM has been inserted. Depending on the type of AIM that has been inserted in the STU/ATU (e.g., installation, telephony, diagnostics, network interface, television, etc.), management information specific to the particular AIM is sent by the STU/ATU upstream to the headend unit. In response, the headend unit provides applications service(s) to the STU/ATU, depending on the particular type of device inserted into the subscriber terminal unit.

Growing community of inventors

Monte Sereno, CA, United States of America

Ali Raissinia