208 results about "Common pilot channel" patented technology

A method and apparatus are provided for defining terminal behavior in a case where the terminal detects that it cannot receive the HS-DSCH from a serving cell reliably when the DCCH is mapped to HS-DSCH (e.g. does not receive any radio link control (RLC) acknowledged mode feedback for the uplink measurement reports or in general the common pilot channel (CPICH) level drops too low in the serving HS-DSCH cell). The terminal is autonomously moved to a cell forward access channel (CELL_FACH) state and uplink signaling is initiated on a random access channel (RACH) to inform a network node and ask for HS-DSCH re-establishment in a suitable cell (preferably in the one being strongest one in the active set or according to the measurements done prior the connection from the serving HS-DSCH cell was lost), or setting up a regular R′99/R′5 DPCH in order to restore the RRC signaling connection in the CELL_DCH state.

Dynamic resource allocation systems, apparatus, and methods are disclosed for selectively improving the ability of a receiver to determine a channel estimate in an Orthogonal Frequency Division Multiple Access (OFDMA) system. A wireless communication system can use a common pilot channel configuration to aid channel estimation in one or more receivers in communication with the system. A receiver in communication with the system may be unable to demodulate received data due to an inaccurate channel estimate. The receiver can communicate to a transmitter in the system a request for additional channel estimation resources. The wireless communication system can provide additional channel estimation resources by inserting dedicated pilot channels into one or more of the frequencies allocated to symbols for the receiver. If the receiver is still unable to demodulate received data, the wireless communication system can incrementally insert additional pilot channels in the symbol associated with the receiver.

A method and apparatus are provided that optimizes a transmitted user-specific signal. In one embodiment, the invention includes receiving signals from a remote radio, deriving estimates of receive channels corresponding to the received signals using the received signals, deriving a model of an expected transmit channel to the remote radio based on the receive channel estimates, deriving a set of transmit parameters to be applied to an array of transmit antennas to transmit a signal to the remote radio by optimizing a transmit power criteria using the model of the expected transmit channel and constraints on the estimated quality of a signal transmitted over the expected transmit channel, and transmitting to the remote radio by applying the derived set of transmit parameters to the transmit antenna array.

A method for synchronizing and identifying the cell code (scrambling code) of a cell in an orthogonal frequency division multiplexing (OFDM) based cellular communication system is provided. In this method, desired cell is found by utilizing a frame structure of OFDM symbols and through a corresponding cell search procedure, where the frame structure has periodic signal pattern and contains the information about the cell code of the desired cell in common pilot channel (CPICH) signal. And, the cell search method utilizes the periodic property of the frame structure to detect frame timing, and the correlation property of CPICH signal to identify the cell code. The cell search method of the present invention offers the advantages of good link quality, fast acquisition, and low power consumption.

A method and apparatus are provided that allows beamforming to be used on a user-specific signal together with a sector-wide pilot signal in a communication system, such as a CDMA system. In one embodiment, the invention includes transmitting a pilot signal with a wide beamwidth to a remote terminal from a first array, transmitting a first traffic signal with a narrow beamwidth directed to the remote terminal from the first array, and transmitting a second diversity traffic signal with a second narrow beamwidth directed to the remote terminal from a second array. In some examples, the invention may also include transmitting a second pilot signal from the second antenna array.

An apparatus and a method are provided for transmitting wireless local area network (WLAN) information in a mobile communication network for WLAN-interworking. The method includes the steps of setting a WLAN threshold value, which is used for determining if a WLAN area is present in a cell, and a measurement period in system information, broadcasting the system information in the cell, and transmitting a common pilot channel, which indicates that the WLAN area is present in the cell, in a predetermined direction with predetermined transmission power to cover the WLAN area by using beam forming.

A phase rotation amount estimating unit (210) rotates a channel estimation value of a signal in a common pilot channel (B) through a candidate phase rotation amount θ (θ=0, 180) for synthesizing with a channel estimation value of a signal in a common pilot channel (A). A phase rotation is estimated based on the highest one of orthogonalities between this synthesis result and channel estimation values of signals in individual channels. A channel estimation value synthesis unit (211) synthesizes a value obtained by rotating a channel estimation value of a signal in the common pilot channel (B) through a phase rotation amount θ with a channel estimation value of a signal in the common pilot channel (A), whereby the reliability of a channel estimation value can be enhanced in a transmission diversity-introduced radio communication system.

A method and apparatus are provided that corrects for differences in reception between a user-specific signal and a common signal. In one embodiment, the invention includes receiving a common pilot signal transmitted on a wide beam at a remote terminal, receiving a user-specific signal transmitted on a directed narrow beam at the remote terminal, demodulating the user-specific signal using the common pilot signal for channel estimation, estimating a phase error in the demodulated user-specific signal using known symbols in the user-specific signal, and correcting for the phase error in the demodulated user-specific signal using the phase error estimates.

A cellular communication system comprising a plurality of geographically spaced base stations (2) each of which comprises an antenna arrangement (4, 6, 8) per base station sector, each of which antenna arrangements has an antenna element for generating an array of narrow beams (10, 12, 14) covering the sector. Timeslots are simultaneously transmitted over each of the beams so as to generate successive sets of simultaneously transmitted timeslots per sector. The timeslots are each split into multiple orthogonal codes, for example Walsh codes. The communication system additionally comprising a scheduling device (31) for allocating for successive sets of timeslots common overhead channels, including a common pilot channel, which are allocated to the same sub-set of codes of each timeslot in the set. For successive sets of timeslots different data traffic is allocated to the same sub-set of codes of each timeslot in the set. This effectively generates a sector wide antenna beam carrying the common overhead channels and a plurality of narrow beams each of which carry different data traffic. Inter-beam interference is addressed by the application of Adaptive Modulation and Coding and by an inter-beam handoff scheme. The handoff scheme ensures that when an end user equipment is located in a cusp region between adjacent beams the antenna arrangement simultaneously transmits data traffic to that mobile station on at least both of the adjacent beams.

A mobile terminal (100) comprises antenna (102), radio unit (104), signal processing unit (110), signal analyzer unit (120), received signal information storage unit (150), and reception quality storage unit (160). Signal processing unit (110) comprises received signal processing unit (112) and notified information processing unit (114), while received signal information storage unit (150) comprises common pilot channel information storage unit (152) and common control channel information storage unit (154). Received signal processing unit (112) measures the reception quality of a common pilot channel and stores it in common pilot channel information storage unit (152). Notified information processing unit (114) extracts transmission power of the common pilot channel and common control channel from report information, and then stores them in common control channel information storage unit (154). Signal analyzer unit (120) calculates the reception quality of the common control channel and the interference signal level, based on the information stored in received signal information storage unit (150).

A method and apparatus for optimizing power settings in a communication system includes a first step (306) of monitoring a noise floor. A next step (308) includes determining if the noise floor crosses a threshold level. A next step (310) includes preventing any further increases in a Common Pilot Channel power level. A next step (312) includes randomly selecting and performing an interference mitigation measure. A next step (320) includes monitoring an interference level. A next step (322) and allowing further increases in a Common Pilot Channel power level if the interference abates by more than a predetermined amount.

The present invention provides a system, method and apparatus for estimating channel parameters in spread spectrum communication systems. A first method is accomplished by receiving a base station signal and then demodulating the base station signal. After demodulating the base station signal, a maximum signal is selected from the base station signal. If the maximum signal is the common pilot channel, then the channel parameters are estimated directly from the common pilot channel. If the maximum signal is not the common pilot channel, then the demodulated base station signal is iteratively fed back for further demodulation and re-selection of the maximum signal until the maximum signal is the common pilot channel. A second method is accomplished by incorporating channel estimates made from the interfering signals in a constructive manner to the first method.

A common pilot channel-use reverse diffusion unit generates common pilot data using a received digital signal and a common pilot channel-use reverse diffusion code, while an individual channel-use reverse diffusion unit generates individual channel data using the received digital signal and an individual channel-use reverse diffusion code. Power calculating unit converts respective output data items of the common pilot channel-use reverse diffusion unit and the individual channel-use reverse diffusion unit into power values, a larger one of which is then determined by a comparator. A selector unit selects the data item having thus determined larger power value of those output data items of those reverse diffusion units. A channel estimating unit estimates the channel using data symbols of the data item thus selected by the selector unit.

Not only pilot channel symbols but also control channel symbols can be flexibly decreased in a radio communication system, which includes a transmission side apparatus transmitting a data frame where a plurality of continuous or discontinuous frequency areas are assigned to one transfer time block and a frame is formed of a predetermined number of transfer time blocks; and a reception side apparatus receiving a data frame from the transmission side apparatus, The transmission side apparatus transmits to the reception side apparatus a data frame which has a common pilot channel and a control channel in the beginning of the frame, the reception side apparatus measures a received quality of the data frame, decides a frame type based on the measured received quality and notifies the decided frame type to the transmission side apparatus. The transmission side apparatus sends subsequent frame data to the reception side apparatus in use of a frame format corresponding to the notified frame type.

The base station broadcasts the system information within the subzone range. Besides the general information of the system information block, the system information includes following information: the available code resources in the downward shared channel used by the adjacent subzone to transmit packet data; the power bias between the public pilot channel and the downward shared channel in the adjacent subzone. The method reduces the possibility that the mobile station soon switches to another subzone from the subzone just switching in since too high load and the poor channel quality. Moreover, the mobile station can use these system informations, combining own measured value to choose best subzone, in order not to waste the system resources.

Methods and systems for diversity processing including using dedicated pilot method for closed loop may include combining a plurality of received WCDMA/HSDPA multipath signals for each diversity transmit antenna to at least one processed diversity signal. The received WCDMA/HSDPA multipath signals may originate from diversity transmit antennas at a base station that may be transmitting information via a closed loop or open loop diversity transmission mode. The closed loop diversity transmission mode may be closed loop 1 or closed loop 2. Estimations may be made of the closed loop transmit weights used by the base station for transmission of the symbols. Closed loop symbols transmitted by the diversity transmit antennas may then be estimated based on received diversity signals and at least one dedicated pilot channel. Open loop symbols may be estimated using information from at least one common pilot channel.

A method for operating a wireless communication system in a cell includes allocating a first plurality of pilot resources to a first frequency sub-band comprising a plurality of high power sub-carriers, allocating a second plurality of pilot resources to a second frequency sub-band comprising a plurality of low power sub-carriers, signaling a power offset between the plurality of pilot resources in the plurality of high power sub-carriers and the plurality of pilot resources in the plurality of low power sub-carriers, and transmitting the first and the second plurality of pilot resources overthe first and the second frequency sub-bands.