Nec Corporation

Other

Nec Electronics Corporation

Michihiro Ohsuge

Tadashi Saito

Tomoaki Hokao

Shinsuke Ogawa

Yutaka Tomiyori

Noriyuki Tsutsumi

Kouiti Tamura

In absence of user data, a bit extracting portiontreats pilot bits as pseudo user data and delivers the pilot bits to a pilot converting portion. The pilot converting portioncarries out symbol rotation with reference to a bit pattern in case where CRC bits alone are transmitted. Those symbols are decoded by a deinterleaving portionand an error correcting portion. A CRC judging portioncarries out CRC judgment.

Communication system and transmission power control method

An antenna-switching diversity receiver is capable of switching antennas without bringing about deterioration of reception characteristics even when applied to the CDMA communication method. A TFCI bit decoding/determination unit decodes TFCI bits that have been extracted by a TFCI bit extractor and determines the presence or absence of communication control data based on the TFCI bits that have been decoded. An antenna switching control unit uses a timer to check for the presence or absence of communication control data in each of fixed time intervals based on the determination results of the TFCI bit decoding/determination unit and then controls the antenna switch in intervals that lack communication control data to measure the reception level of the common pilot channel at the other antenna that differs from the antenna that is currently receiving and then select the antenna having the higher reception level.

Antenna-switching diversity receiver capable of switching antennas without deterioration of reception characteristic even when applied to the CDMA communication method

The present invention provides a TFCI decoding circuit and decoding method in which the TFI information for a relevant transport channel is determined, employing all the TFCI codeword information within the TTI, to enhance the receiving performance. A TTI combination pattern generating unit generates as a TTI combination pattern all the possible combinations of TFCI within a TTI having the longest interval among the TTIs for a plurality of transport channels, based on the fact that the TFI of a certain transport channel is not changed within the TTI on the transport channel. An adder adds, for each pattern, the likelihood for each radio frame calculated by a likelihood calculating unit, based on the TTI combination patterns. A TFI determination unit determines the TFI number of a relevant transport channel by selecting a pattern having the highest likelihood from among the TTI combination patterns.

TFCI decoding circuit and decoding method

In a multi-path detection circuit for use in a CDMA communication system, a first peak is detected by searching a maximum value over a whole of data blocks composed of delay profile data. A second and the following peaks are detected by carrying out maximum value searching operation again only about a data block that is renewed in the delay profile data. As the remaining data blocks, a maximum value searched a previous time is preserved and used a next time and, therefore, reduction is possible in connection with the number of detection cycles necessary for detecting the second and the following peaks.

Multi-path detection circuit and method for a CDMA receiver

A receiver of a spread spectrum communication system comprises a plurality of despreading circuits, a rake circuit, and a path searcher. The plurality of despreading circuits despreads received signals having multipath components at predetermined timing allocated thereto. The rake circuit performs rake combining of the signals despread by despreading circuits. The path searcher forms a first window showing a part of a search range and calculates delay profile data of said received signals in said first window to search an effective path, forms at least one second window in the search range except said first window and calculates delay profile data of said received signals in said second window, and detects timing at which said received signals are despread based on calculated delay profile data to allocate the detected timing to said despreading circuits.

Path search method of spread spectrum communication system and receiver using the method

A multi-path detection circuit can improve path detection accuracy in the environment where the path is located close in the extent of one chip in the multi-path detection circuit of CDMA type receiver unit. The multi-path detection circuit has generating means for generating a logic pattern of a correlated peak in the delay profile, and removing means for removing a power component of the detected correlated peak from the delay profile using the logical pattern of the correlated peak generated by the generating means.

Pattern generation circuit, multi-path detection circuit employing the same and multi-path detection method

When the number of fingers assigned to a branch signal is smaller than the aimed number and there is a path to be added, the search is performed for an unused finger, firstly, and for one of fingers, the number of which is larger than the aimed number and which are assigned to the branch signal, which has the lowest receiving signal level, secondly. When the aimed number of fingers is satisfied and there is a path to be added, an unused finger is used if any and, when there is only an effective finger, the number of fingers assigned to a branch signal is not increased.

CDMA receiver and CDMA receiving method

A method of allocating a plurality of paths to finger receivers by multiplying a delay profile by a weighting coefficient to provide hysteresis for detection of path timing is disclosed. Signals received at an antenna are down-converted at a high-frequency reception circuit and converted to digital signals at an A/D converter. A sliding correlator derives a delay profile from the digitally converted signals. A delay profile power adder averages path variations due to fading or the like for the delay profile. The delay profile after the path variations are averaged is multiplied by a weighting coefficient from a state weighting section at a multiplier in a weighting unit. A correlation peak position detecting unit detects upper N path timing from the delay profile multiplied by the weighting coefficient. The detected path timing is notified from a rake path allocating unit to respective finger receivers.

Method of providing hysteresis in detection of path timing by multiplying delay profile by weighting coefficient

A CDMA receiver includes a Rake reception circuit for performing in-phase synthesis of reception signals from a plurality of paths. In this receiver, a delay profile indicating a signal power distribution with respect to delay times of the reception signals is measured. An interference wave power value is estimated on the basis of the measured delay profile. Valid data are extracted from the delay profile on the basis of the estimated interference wave power value. A plurality of correlation peak positions are detected from the extracted valid data. Path allocation to the Rake reception circuit is determined on the basis of the correlation peak positions. A path detection method and recording medium which records a path detection control program are also disclosed.

CDMA receiver, path detection method, and recording medium on which path detection control program is recorded

A path timing detecting circuit can save consumed current by omitting correlative arithmetic operations (cumulation) for unnecessarily long correlation lengths L when a propagation environment is relatively good, and a plurality of paths can be detected with high precision. The path timing detector circuit performing a correlative arithmetic operation of a spread modulation wave and a predetermined spread code with a given period of delay and detecting a reception timing of the spread modulation signal via each path on the basis of a result of the correlative arithmetic operation, includes a monitoring circuit for monitoring whether a cumulated value exceeds a threshold value during a process of the correlative arithmetic operation and a correlative arithmetic operation control circuit responsive to the cumulated value in excess of the threshold value for stopping the correlative arithmetic operation in a corresponding delay period.

Path timing detection circuit and detection method thereof

At providing a voice recording function for a mobile telephone, an additional circuit is small and the simplification of the circuit is possible, in case of that more voice data are preferred to be stored, the voice data of PHS are able to be further compressed and stored and the recording time is able to be increased and user himself can select the priority of the voice quality or the recording the time, the above mentioned mobile telephone is provided. At the mobile telephone having plural voice encoding system, the mobile telephone provides an encoding/decoding means, a voice data storing means, a decoding and playback means, a decoded data storing means and a data compression means. The encoding/decoding means provides a voice codec section, a controller and a recording key, and encodes and decodes the voice corresponding to a first voice encoding system. The voice data storing means provides a voice data memory and stores encoded voice data. The decoding and playback means provides the controller, the voice data are decoded and played back at arbitrarily time. The decoding means provides three decoders, the controller and the recording key, and decodes the stored data of the first voice encoding system at arbitrary time. The decoded data storing means provides a data buffer storing the decoded data temporarily. The data compression means provides a compression key, the controller and three encoders, and stores re-encoded data by a second voice encoding system in the voice data memory and compresses the data.

Mobile telephone with voice data compression and recording features

At providing a voice recording function for a mobile telephone, an additional circuit is small and the simplification of the circuit is possible, in case of that more voice data are preferred to be stored, the voice data of PHS are able to be further compressed and stored and the recording time is able to be increased and user himself can select the priority of the voice quality or the recording time, the above mentioned mobile telephone is provided. At the mobile telephone having plural voice encoding system, the mobile telephone provides an encoding/decoding feature, a voice data storing feature, a decoding and playback feature, a decoded data storing means and a data compression feature. The encoding/decoding feature provides a voice codec section, a controller and a recording key, and encodes and decodes the voice corresponding to a First voice encoding system. The voice data storing feature provides a voice data memory and stores encoded voice data. The decoding and playback feature provides the controller, the voice data memory, the recording key and three decoders, and the stored voice data are decoded and play backed at arbitrarily time. The decoding feature provides three decoders, the controller and the recording key, and decodes the stored data of the first voice encoding system at arbitrary time. The decoded data storing feature provides a data buffer storing the decoded data temporarily. The data compression feature provides a compression key, the controller and three encoders, and stores re-encoded data by a second voice encoding system in the voice data memory and compresses the data.

In placing a call, a destination telephone number entered through the keyboard section,is saved in a storage device,. A signal indicating that a line cannot be connected (BUSY signal) enters into a BUSY measurement section,from a base station through a radio section,. When it continues for a predetermined period of time, a control section,automatically changes over the mode to another system mode, and automatically places a call to a telephone number saved in a storage device,. Thus, a communication system in which a line is empty can be searched with single outgoing operation, so that operability is improved.

Radio communication apparatus and control method therefor

A portable electronic apparatus having an adjustable ringing tone volume, a light receiving element 4 for detecting external light and a control circuit 3 for controlling he tone volume in response to light detection by the light receiving element 4. When the light receiving element 4 detects light as the power supply is turned on, or a specified key arranged on the external face of the housing is pressed down, the control circuit 3 causes a loudspeaker 7 to sound a test tone, picks up its echo with a microphone 5, and stores the volume of the echo into a memory 6 as a reference volume level. The control circuit 3, when notified of the arrival of a call by a transmitter/receiver circuit 2, causes the loudspeaker 7 to sound a test tone unless the light receiving element 4 detects light, picks up its echo with the microphone 5, and compares the volume of the echo with the reference volume level stored in the memory 6. The control circuit 3, if it finds the volume of the echo greater than the reference volume, will increase the volume of the ringing tone from the loudspeaker 7. The control circuit 3, when detecting a change in ambient light (by the light receiving element 4), switches the means of notice of call arrival from the sounding of the ringing tone by the loudspeaker 7 to intermittent lighting by an LED 8.

Growing community of inventors

Tokyo, Japan

Michihiro Ohsuge