5883results about "Code division multiplex" patented technology

A proximity measuring apparatus (70) comprises an interrogator (80) for generating an interrogation signal encoded with a reference signature code comprising concatenated codes and emitting it as interrogating radiation. It also incorporates a transponder (90) for receiving the interrogating radiation, demodulating it to extract its signature code and then remodulating it after a delay period to provide a signal for reemission as return radiation therefrom. The interrogator (80) receives return radiation at its antenna (260) and demodulates it to extract its signature code and then correlates the code with the reference code to determine mutual correlation thereof. The interrogator (80) incorporates a computer (290) for controlling a scan direction of the antenna (260) and for measuring time delay between emission of the interrogating radiation therefrom and receipt of corresponding return radiation. The computer (290) computes distance and relative bearing of a transponder (90) providing the return radiation from the scan direction and the time delay. The apparatus (70) may be used for improving road vehicle safety.

A system and method for initializing a system communication without previous reservations for random access channel (RACH) access includes a first step of defining at least one spread sequence derived from at least one constant amplitude zero autocorrelation sequence. A next step includes combining the spread sequence with a Walsh code to form an extended spread sequence. A next step includes using the extended spread sequence in a preamble for a RACH. A next step includes sending the preamble to a BTS for acquisition. A next step includes monitoring for a positive acquisition indicator from the BTS. A next step includes scheduling the sending of a RACH message. A next step includes sending the RACH message.

In a method for transmitting a contention free scheduling request in a cellular network, a set of N frequency opportunities is defined within a scheduling request slot. A set of R CAZAC root sequences is then defined per frequency opportunity. A set of C cyclic shifts is then defined per CAZAC root sequence. Within a given cell, a unique identification number is assigned to each user equipment (UE) that is in an uplink (UL) synchronized state. Each UL synchronized UE is mapped to a unique combination of one of the N frequency opportunities, one of the R CAZAC root sequences and one of the C cyclic shifts. A cyclic shifted preamble sequence for a given UE is transmitted as a scheduling request on the mapped frequency, CAZAC root sequence and cyclic shift opportunity, wherein the unique identification number of the given UE is encoded by the combination of the frequency opportunity, CAZAC root sequence opportunity, and amount of cyclic shift, such that up to all of the plurality of UE can transmit a schedule request (SR) in a non-contentious manner in one schedule request slot.

The present invention provides a method for realizing transmission of multiprotocol client signals in a distributed base station subsystem, comprising: encapsulating client signals by a GFP-T frame; and mapping said GFP-T frame into a lower-layer transmission link to realize the transmission of client signals. Said lower-layer transmission link is a common public radio interface CPRI link. Said client signals are one of the following: baseband I/Q signals of WCDMA supported by CPRI protocol, baseband I/Q signals of radio interface protocols other than WCDMA, structured signals of E1/T1, STM-1 and other constant-rate links, structured variable-rate link signals such as Ethernet MAC frame signals, PPP/HDLC frame signals, etc. This method is also applicable to other types of synchronous transmission links between a remote radio unit and a primary baseband processing unit, e.g., the links as specified by OBSAI (Open Base Station Architecture Initiative).

Techniques are provided to support fast frequency hopping with a code division multiplexed (CDM) pilot in a multi-carrier communication system (e.g., an OFDMA system). Each transmitter (e.g., each terminal) in the system transmits a wideband pilot on all subbands to allow a receiver (e.g., a base station) to estimate the entire channel response at the same time. The wideband pilot for each transmitter may be generated using direct sequence spread spectrum processing and based on a pseudo-random number (PN) code assigned to that transmitter. This allows the receiver to individually identify and recover multiple wideband pilots transmitted concurrently by multiple transmitters. For a time division multiplexed (TDM)/CDM pilot transmission scheme, each transmitter transmits the wideband pilot in bursts. For a continuous CDM pilot transmission scheme, each transmitter continuously transmits the wideband pilot, albeit at a low transmit power level. Any frequency hopping rate may be supported without impacting pilot overhead.

The invention provides a mechanism for automatically setting reverse link gain or power for a repeater (120) used in a communication system (100) through the use of the reverse link power control of a built-in wireless communications device. By embedding a wireless communication device (430, 630, 700) inside the repeater and injecting reverse link signals of the embedded device into the reverse link of the repeater (124A, 124B), the gain of the repeater is maintained relatively constant. The embedded WCD can also be activated on a periodic basis to make calls and utilize reverse link power-control to calibrate or re-calibrate the gain of the repeater, making it a power-controlled repeater.

A radio communication system and method having an array antenna and a weighting arrangement that provides a downlink array weight for a downlink on the basis of information about bearings of a plurality of incoming signals received through a plurality of uplinks, and transmission power control information about transmission data to be transmitted through a downlink.

A method and apparatus of transmitting a reference signal in a wireless communication system is provided. The method includes generating a precoded reference signal or a non-precoded reference signal in accordance with a rank, and transmitting the generated reference signal. Uplink transmission using multiple transmit antennas is supported through reference signal design and related control signaling.

Techniques to support independent power control of multiple channels in CDMA systems (e.g., a W-CDMA system) that define a single power control feedback stream on the uplink, which is to be used for downlink power control. In one aspect, the single feedback stream is "time shared" among multiple channels requiring individual power control. Various time-sharing schemes may be used to implement multiple (substantially parallel) feedback substreams based on the single feedback stream, and different combination of feedback rates may also be achieved for the substreams. Each feedback substream may be assigned to, and used for power control of, a respective channel. In another aspect, multiple feedback substreams are implemented based on multiple fields in newly defined slot formats.

A WCDMA system includes a Base Station (BS) transmitter, or forward transmitter and a pilot channel that transmits control signals between the BS and a Mobile Station (MS) to reconfigure their transmitter/receiver. Reconfiguration is performed according to the prediction of the channel attenuation and the threshold set at the BS or MS based on its channel power probability density function separated into three distinct equal probable regions. In one embodiment, Seamless Rate Change (SRC)/Transmitter Power Control (TPC) logic uses the predicted channel attenuation to signal both the transmitter and the receiver in a channel to reconfigure their transmit power level according to the power density function (pdf) of the channel power and threshold level. A transmission rate is reduced when the power level is below the threshold and increased when the channel power is above threshold. The pilot channel is used to signal the mobile station and the base station.

A radio network controller (RNC) transmits a power offset for controlling transmission power of an uplink high-speed dedicated physical control channel (HS-DPCCH) when a user equipment (UE) enters a handover region, in a mobile communication system including the RNC, a Node B connected to the RNC, and the UE located in one of at least two cell areas occupied by the Node B. The Node B transmits data to the UE over a high-speed downlink shared channel (HS-DSCH) and the UE transmits information indicating reception of the data to the Node B over the uplink HS-DPCCH. The RNC informs the UE of a power offset for determining a transmission power increment of the uplink HS-DPCCH, if it is determined that the UE is located in the handover region. The RNC informs the Node B of the power offset so that the Node B can determine a threshold value for determining information indicating reception of the data, depending on the power offset.

Embodiments of the present invention include one or more wireless transmitting devices and an array of receiver units for receiving wireless communications from the transmitting devices. The transmitter devices and receiver units can be arranged in one, two or three dimensional configurations. Signals are transmitted from the devices for identification and accurate location determination. Spread spectrum techniques can be used, such as DSSS, FHSS, THSS, and pseudo-noise (PN) coding schemes, or combinations thereof. The transmitting devices can generate one or a plurality of data signals that are orthogonal-code modulated, to be decoded by the receiver units and a processor associated therewith. A plurality of transmitter signals can be received, identified, located, and data demodulated substantially simultaneously using embodiments of the invention. The combined use of array processing methods and diversity schemes can be used to reduce the effects of signal multi-path and occlusion.

An efficient communications apparatus is described for a vector signaling code to transport data and optionally a clocking signal between integrated circuit devices. Methods of designing such apparatus and their associated codes based on a new metric herein called the “ISI Ratio” are described which permit higher communications speed, lower system power consumption, and reduced implementation complexity.

Methods and apparatus for supporting and using multiple communications channels corresponding to different transmit technologies and/or access technologies in parallel within a cell of a wireless communications system are described. Mobile nodes support multiple technologies and can switch between the technology being used at a particular point in time, e.g., from a first channel corresponding to a first technology to a second channel corresponding to a different technology which provides better transmission characteristics, e.g., a better perceived channel quality. Mobiles maintain at least two sets of channel quality information at any one point in time. Mobiles select the better channel and communicate the channel selection to the base station or communicate channel quality information for multiple channels to the basestation and allow the base station to select the channel corresponding to the technology providing the better conditions for the mobile. Different mobiles in the same cell may support different technologies.

In a wireless network comprising a plurality of subscriber stations and a base station capable of providing service to the subscriber stations, a subscriber station is provided that includes a rank selector and a scheduling data reporter. The rank selector is operable to select a rank for the subscriber station. The rank is operable to identify a number of antennas for transmitting data streams from the base station to the subscriber station. The scheduling data reporter is operable to report scheduling data, including the rank, to the base station.

In an adaptive modulation and coding method one or more adjustable values are created (S1), each corresponding to at least one of a plurality of available modulation and coding levels applicable to a signal transmitted from a transmitter to a receiver, and each representing a change to the level(s) to which it corresponds. One or more of said adjustable values is/are adjusted in dependence upon whether or not the signal is received successfully by the receiver (S2-S5). One of said available modulation and coding levels is selected (S6-S8) to apply to the signal based on such an adjustable value. Such a method can enable the appropriate modulation and coding level to be selected even when the path and channel conditions vary. The method is applicable to selecting modulation and coding levels in a high-speed downlink packet access system of a wireless communication network.