694 results about "Cdma communication" patented technology

A receiver of the present invention addresses the need for improved interference suppression without the number of transmissions by the power control system being increased, and, to this end, provides a receiver for a CDMA communications system which employs interference subspace rejection to tune a substantially null response to interference components from selected signals of other user stations. Preferably, the receiver also tunes a substantially unity response for a propagation channel via which a corresponding user's signal was received. The receiver may be used in a base station or in a user/mobile station.

Disclosed is a code division multiple access (CDMA) communication system having a downlink dedicated physical channel (DL_DPCH) having a downlink dedicated physical control channel (DL_DPCCH) and a downlink dedicated physical data channel (DL_DPDCH). The DL_DPCCH having a transport power control (TPC) field transmitting a TPC command for controlling uplink transport power, a transport format combination indicator (TFCI) field transmitting TFCI indicating a transport format combination of a currently transmitted channel, and a pilot field transmitting a pilot. The DL_DPDCH has first and second data fields transmitting downlink data. If data is normally received over an enhanced uplink dedicated channel (EUDCH), ACK information is generated, and if data is abnormally received over the EUDCH, NACK information is generated. Bits corresponding to the ACK or NACK information are punctured at a position randomly selected from the first and second data fields of the DL_DPDCH, and the ACK or NACK information is inserted into the punctured position before being transmitted.

Techniques to more accurately measure the arrival times of transmissions received at a remote terminal from a number of base stations. In one aspect, unassigned finger processors are used to process and measure the arrival times of transmissions from base stations not in the active set. In another aspect, if no finger processors are available for assignment, the arrival times can be measured in the time period between updates of a reference oscillator used for the measurements. In accordance with a method for determining a position of a remote terminal, a first set of one or more base stations in active communication with the remote terminal is identified and each base station in the first set is assigned at least one finger processor. A second set of one or more base stations not in active communication with the remote terminal is also identified and an available finger processor is assigned to each of at least one base station in the second set. A (signal arrival) time measurement is then performed for each base station, and outputs indicative of the measurements are provided for further processing. To improve accuracy, the measurements can be performed within a narrow time window.

A transceiver includes a transmitter and a homodyne receiver, wherein the receiver is used to process both antenna-received and antenna-reflected signals. Thus, during a receive mode, for example, the receiver downconverts antenna-received signals to baseband signals, which are then processed to recover receive signal information. Then, during a transmit mode for example, antenna-reflected transmit signals are fed back to the receiver, which is retuned to the desired transmit frequency, and thus downconverts the reflected transmit signals to baseband signals. These baseband signals are then processed to obtain a characterization of impedance mismatch between the transceiver's transmitter and the associated antenna. An adjustable matching network disposed in the transmit signal path thus may be adjusted based on the characterization to reduce the mismatch. Such configurations may be used with either single-band or multi-band embodiments of the transceiver, and the transceiver may be used in both TDMA and CDMA communication systems.

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 forward link device of a multicarrier CDMA communication system with an overlay scheme in which a multicarrier system and an IS-95 system share same frequency bands. In the forward link device, four encoders encode input data of corresponding rates with a 1/3 coding rate, respectively. A first repeater repeats two times full rate symbols output from the first encoder, and second to fourth repeaters repeat symbols output from the second to fourth encoders, respectively, according to a predetermined number of times, to match the number of corresponding output symbols to the number of full rate symbols. First to fourth interleavers interleave the symbols output from the first to fourth repeaters, respectively, to uniformly distribute the symbols of the same data bit to the carriers.

A method for broadcasting channel information, available channel and data rate of a base station in a CDMA communication system. The base station receives information indicating that a mobile station has data to transmit, over an access preamble channel. The base station transmits use status information of physical channels and maximum available data rate information on a status indicator channel. The mobile station receives the use status information of physical channels and the maximum available data rate information through the status indicator channel from a base station. The mobile station transmits to the base station an access preamble for requesting allocation of a given physical channel determined depending on the use status information and the maximum available data rate information.

A cellular radio system in which a base station receiver can receive, on the reverse link, data from a mobile terminal in one of four control modes. In the first mode, the mobile terminal sends an independent user pilot, not synchronized with the base station, on the reverse link and the user data channel is synchronized to this independent user pilot. In the second mode, the mobile terminal slaves its user pilot to the pilot it receives from the base station and the user data channel is synchronized with this slaved user pilot. This second mode allows the user terminal to receive round trip delay information for purposes of geolocation and rapid reacquisition. In the third mode, the mobile terminal slaves its user pilot to the incoming base station pilot, as in the case of mode two, but the user data channel operates in the orthogonal mode using the ranging information received from the base station. The phase relationship between the user pilot channel and the user data channel is calibrated. The user pilot carrier is also the carrier for the user data channel and can be used as the carrier reference for detecting the user data channel. In the fourth mode, the slaved pilot implementation of mode three is used for acquisition but, after acquisition, the user pilot code is phase shifted to be synchronous with the user data channel, thus also making it an orthogonal channel. In this mode, the pilots no longer contribute interference to the user data channels, within the cell, and can be transmitted at higher power levels.

The invention relates notably to a method for modulating information symbols to be transmitted in a CDMA communication network by using a non-orthogonal modulation code comprising M spreading sequences (s_m 1≦m≦M), each comprising in N chips (s_m,n 1≦n≦N), the M spreading sequences having the same energy.

According to the invention, the amplitude of the chips take a plurality of values the number M of spreading sequences is higher than the number of chips N per spreading sequence.

A signal is received at a component of the wireless CDMA communications system, such as a base station or satellite gateway. A plurality of data sets is generated from the received signal, respective ones of the plurality of data sets corresponding to respective access probes received, for example, over the reverse access channel (R-ACH) or reverse enhanced access channel (R-EACH). At least some of the plurality of data sets are jointly decoded to recover an access probe payload.

A multi-user receiving apparatus for inputting a CDMA reception signal, performing an interference canceling process in parallel for each user signal on an m-th stage of M stages (where m is any integer of 1<=m<=M; and M is any integer of M >=2), and outputting demodulated signals on the M-th stage is disclosed, that comprises a plurality of IEUs (interference estimating units) disposed corresponding to the (M-1) stages and the number of user signals, and a plurality of subtracting units disposed corresponding to the (M-1) stages, wherein each of the IEUs Inputs an interference cancellation residual signal obtained in an (m-1)-th stage interference canceling process and a signal of which a symbol replica corresponding to the same user signal on the (m-1)-th stage is weighted with a first weighting coefficient, generates an m-th stage symbol replica, outputs the m-th stage symbol replica to the (m+1)-th stage, and outputs a spread signal that is the difference between the m-th stage symbol replica and the (m-1)-th stage symbol replica weighted with the first weighting coefficient, and wherein each of the subtracting units subtracts signals of which the spread signals that are output from the IEUs on the m-th stage are weighted with a second weighting coefficient from a signal of which the (m-1)-th stage interference cancellation residual signal is delayed by a predetermined value and outputs the resultant signal to the (m+1)-th stage.

A method of reducing paging channel usage in a CDMA communication system. Each mobile switching centre maintains in its visitor location registry information regarding a paging channel or carrier frequency that each mobile station registered is monitoring. Then, when it comes time to send a page to a mobile station, the mobile switching centre looks up the information and appends it to the page which is sent to all basestation transceivers. The basestation transceivers extract the information and identify the paging channel the mobile station to which the page is addressed is monitoring. The transceivers then broadcast the page message over their air interfaces on the identified paging channel.

Techniques for delivering data recovered by a HARQ entity in proper order to higher layers in a CDMA system. In a method, packets are received from the HARQ entity by the re-ordering entity and missing packets among the received packets are detected. Packets may be transmitted in a sequential order based on transmission sequence numbers (TSNs) assigned to the packets, and missing packets may be detected based on the TSNs of the received packets. Delivery of received packets later than the missing packets are stalled because higher layers expect data in-order. A determination is thereafter made whether each missing packet is (1) subsequently received from the HARQ entity or (2) lost, by successively eliminating HARQ channels that may be used to send the missing packet. Received packets previously stalled by each missing packet are delivered after the missing packet is determined to be lost or received.

Disclosed is a method for indicating an end of transmitting data frames in order to enable a UTRAN (UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network) to assign a common packet channel to another user equipment (UE) in a UE for a CDMA mobile communication system. The UE requests assignment of any one of a number of common packet channels assignable in the UTRAN; the UE is assigned a common packet channel by the UTRAN in response to the to request; the UE sequentially transmits the data frames and their associated control frames over the assigned common packet channel; and the UE transmits at least one control frame, in an appointed field of which a given bit pattern appointed with the UTRAN is registered, in order to inform the UTRAN of an end of data transmission upon completing data transmission through the data frames.

An apparatus and method for gated transmission in a CDMA communication system. A mobile station in the CDMA communication system transmits a reverse pilot signal at a reverse gating rate different from a forward gating rate in a gated mode in a control hold state, and a base station transmits a forward pilot signal at the forward gating rate different from the forward gating rate in a gated mode.

A method for determining a gating rate in a base station for a CDMA communication system is disclosed. The method comprises transmitting information for assigning a dedicated control channel and a traffic channel to a mobile station, when a call is generated; after call setup, transmitting a message requesting mobile station's capability information to the mobile station; receiving the capability information including gating availability information of a reverse pilot signal and information about at least one gating rate, transmitted from the mobile station in reply to the request message; and determining a gating rate according to the capability information, transmitting information about the determined gating rate to the mobile station, and transitioning to an active sate. The mobile station's capability information includes information about gating availability and at least one gating rate, when gating is available.

The location of a mobile wireless communication unit in the service area of a CDMA communications system is predicted utilizing two likelihood functions that define maximum likelihood estimators of the mobile unit's location, based on attribute measurements, such as but not limited to pilot signal strength, being made at the location of the mobile unit and reported back to a base station. One of the likelihood functions comprises a frequentist likelihood function and the other comprises a Bayesian-modified likelihood function. The likelihood functions are based on the assumption that there is an RF model which provides the probability a mobile unit is able to detect one or more attributes associated with an arbitrary base station, given it is located at an arbitrary location within the service area. Each of the likelihoods are also incorporated into a sequential Bayesian procedure which outputs a posterior distribution indicative of the location of the mobile unit.

A TDD (Time Division Duplexing) CDMA (Code Division Multiple Access) communication system performs power control in a closed-loop power control mode in a data transmission period, but performs the power control using a modified open loop power control method and an open loop power control method as well as the closed-loop power control method in a transmission pause period, thereby to properly set initial transmission power after the end of the transmission pause period.

A method for transmitting pilot bits instead of partial bits of CQI (Channel Quality Indicator) information indicating channel quality of an HS-PDSCH (High Speed-Physical Downlink Shared CHannel) in a CDMA (Code Division Multiple Access) communication system such that a Node B can control power of a high-speed uplink control channel. The system transmits high-speed packet data from the Node-B to UE (User Equipment) through the HS-PDSCH, and the UE is located in a handover area between the Node-B and another Node-B adjacent thereto. Predetermined bits are then removed from given bits of the code symbols. The removed bits are then replaced with high-speed pilot bits for power control.

Apparatus, and an associated method, for controlling RLP logical layer operations of a communication station, such as a mobile station or base transceiver station of a CDMA communication system that provides for both 1xRTT and 1xEV-DV communications. Modifications to existing data service options at the RLP logical layer are provided to facilitate RLP operations.

A system and method involve tracking the location of objects within an area of interest using transmitted-reference ultra-wideband (TR-UWB) signals. The system includes at least three base stations communicating with a central processor, at least one mobile device and at least one fixed beacon transmitter of known location. The mobile device is equipped with a transmitter for transmitting a TR-UWB signal to a base station, which then determines a location of the mobile device based on time difference of arrival information between the beacon transmitters and mobile devices measured at all the base stations. Preferably, the area of interest includes a plurality of mobile devices each transmitting a delay-hopped TR-UWB signal according to a code-division multiple access scheme. The mobile devices may be attached to a patient and/or a medical asset within the hospital for tracking purposes. Additionally, patient medical information may be transmitted with the TR-UWB signals to allow patient monitoring to occur simultaneously with asset/patient tracking.

A timing error compensation system in an OFMD/CDMA communication system includes an analog-to-digital converter for converting an OFDM signal, comprised of a data symbol stream in which a pilot symbol is inserted at intervals of a prescribed number of data symbols, received from a transmitter, to a digital OFDM symbol stream by prescribed sampling synchronization, a guard interval remover for removing a guard interval inserted in the OFDM symbol by prescribed frame synchronization, and a fast Fourier transform (FFT) device for performing fast Fourier transform on the guard interval-removed OFDM symbol and outputting a data symbol stream. In the time error compensation system, a pilot symbol detector receives the data symbol stream and detects the pilot symbols inserted in the data symbol stream at prescribed intervals. A timing compensator determines a linear phase difference line for the detected pilot symbol, generates a timing error estimation signal according to the determined linear phase difference line, and provides the timing error estimation signal to the analog-to-digital converter and the guard interval remover so as to determine the sampling synchronization and the frame synchronization.

Disclosed is a channel allocation method in a CDMA communication system. The method comprises receiving from a UTRAN one SF node C_SF,k out of 2^m−1 SF nodes (where m is an integer larger than 3) arranged in the form of a tree having a mother node and child nodes; searching a group including the received SF node C_SF,k in accordance with Formula (1) below; spreading a signal on a dedicated physical data channel (DPDCH) with an OVSF code corresponding to a selected one of the received SF node and its child nodes in the searched group; and spreading a signal on a dedicated physical control channel (DPCCH) with an OVSF code corresponding to an SF node determined by Formula (2) below based on the received SF node. $\begin{array}{cc}\mathrm{For}\mathrm{SF}\le \frac{2^{m-1}}{4},\left(P_1·\mathrm{SF},P_1·k\right)=\left(\frac{2^{m-1}}{4},n\right)\mathrm{For}\mathrm{SF}>\frac{2^{m-1}}{4},\left(P_2·\frac{2^{m-1}}{4},P_2·n\right)=\left(\mathrm{SF},k\right)\mathrm{where},P_1=\frac{2^{m-1}}{4·\mathrm{SF}}\mathrm{and}{P}_2=\frac{4·\mathrm{SF}}{2^{m-1}}.& \text{Formula (1)}\\ F\left(C_{\frac{2^{m-1}}{4}·k}\right)=C_{2^{m-1}{2}^{m-1}-k-1}(k=0,1,\dots )F\left(C_{\frac{2^{m-1}}{4}·k}\right)=C_{2^{m-1},2^{m-1}-\left(k-32\right)}(k=0,1,\dots ).& \text{Formula (2)}\end{array}$

Disclosed is a method for controlling uplink transmission power in a handover region by a UE in communication with a Node B using an FCS scheme. The UE stores TPC commands received for a specific duration from a plurality of cells in an active set, if the UE enters in the handover region during communication with a current best cell. If a next best cell is selected from the plurality of the cells, the UE determines a transmission power offset by comparing TPC commands from the current best cell with TPC commands from the next best cell for the specific duration at a time point where the best cell is changed from the current best cell to the next best cell. The UE transmits initial transmission power for the next best cell at a transmission power level determined considering the transmission power offset.