This paper presents the concept, principles, and analysis of maximum ratio transmission for wireless communications where multiple antennas are used for both transmission and reception. The principles and analysis are applicable to general cases, including maximum ratio combining. Simulation results agree with the analysis. The analysis shows that the average overall SNR is proportional to the cross-correlation between channel vectors and that error probability decreases inversely with the (L/spl times/K)th power of the average SNR.

Maximum ratio transmission

Provided are a radio transmission device and a radio transmission method capable of improving downlink and uplink throughput even when performing dynamic symbol allocation. In the device and the method, BS and MS share a table correlating a basic TF as a combination of parameters such as TB size used for transmitting only user data, an allocation RB quantity, a modulation method, and an encoding ratio, with a derived TF having user data of different TB size by combining L1/L2 control information. Even when multiplexing L1/L2 control information, Index corresponding to the basic TF is reported from BS to MS.

Radio transmission device and radio transmission method

Described herein are power receptacle wireless access point (AP) devices that may be used as part of a networked (smart) living and work space. These power receptacle wireless AP devices may be wall-mounted and/or retrofitted over existing electrical outlets or light switches, for providing wireless access to a room or region of a room. The power receptacle wireless AP device may connect via power line communication to a data connection.

Power receptacle wireless access point devices for networked living and work spaces

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.

Apparatus and method for assigning a common packet channel in a cdma communication system

A method for interference mitigation in a wireless communication system having multiple transmitters and receivers by introducing transmission time delays between the transmission of signals from the individual transmitters to ensure coherent reception of the signals at a specific point in the coverage area, such as at a center of distribution of the receivers. To further aid in interference mitigation the signals are assigned training patterns chosen to be distinguishable by the receiver and to optimize interference mitigation. The training patterns can be selected based on a feedback parameter, e.g., a measure of the quality of interference mitigation obtained from the receiver. The present method can be used in wireless communication systems which re-use frequencies including TDMA, CDMA, FDMA, OFDMA or other multiplex communication systems using a multiple access method or a combination of such methods.

Method and wireless communications systems using coordinated transmission and training for interference mitigation

The present invention employs one or more complementary sequences, e.g., Golay pairs of sequences, to provide accurate and efficient synchronization between radio transceivers. A matched filter corresponding to a complementary pair of sequences is used to correlate the received signal with one of the complementary pair of sequences. A peak output is detected from the matched filter, and the detected peak is used to generate a timing estimate for synchronizing transmissions between transceivers. Each of the complementary sequences has minimal aperiodic autocorrelation sidelobe values for all non-zero delays of that complementary sequence and a maximal autocorrelation main lobe value for a zero delay of that complementary sequence. The one sequence may be used as a preamble portion of a random access message transmitted by a mobile station to a base station over a random access channel. The sequence may also be used as a synchronization code transmitted by the base over a synchronization channel and used by mobile stations to obtain synchronization. An efficient Golay correlator and a bank of efficient Golay correlators for correlating respectively with a single sequence and with a set of orthogonal sequences are disclosed.

Method and apparatus for efficient synchronization in spread spectrum communications

The invention relates to a multipath propagation delay determining means (STU, FIGS. 6, 7 ) for determining a power delay spectrum (DPS) of a CDMA signal transmission between a CDMA base station (BS) and a CDMA mobile station (MS) on a plurality of propagation paths (P 1 , P 2 ) within a cell (CL) of a CDMA communication system, comprising an A/D conversion means (A/D) for converting an analog CDMA multipath signal (S 1 , S 2 ) received from at least one antenna (Ant 1 , Ant 2 ) within said cell (CL) into a digital CDMA multipath signal (S 1 , S 2 ) consisting of consecutive radio frames (RF 1 . . . RFn) including consecutive time slots (TS 1 . . . TSm) with complex pilot symbols (PSi) and data symbols (Pdi), a demultiplexing means (PI-DEMUX) for extracting complex pilot symbols (PSi) and data symbols (PDi) from at least two consecutive time slots (TSk−1, TSk, TSk+1) of each radio frame (RFn) and for storing them consecutively in a memory means (BUF) thereof; and a searching means (S 1 . . . SL) for determining a power delay profile (DPS, DPS 1 , DPS 2 , FIG. 14 ) of said each antenna (Ant. 1 , Ant. 2 ) on the basis of said extracted and stored complex pilot symbols and said data symbols (PSi, PDi).

Multipath propagation delay determining means using periodically inserted pilot symbols

Using measured estimates of received signal energy and interference values, a measured signal-to-interference ratio (SIR) value is determined. The measured SIR value is corrected for non-linearity to obtain a corrected SIR value using a correction function. That corrected SIR value may then be used in any number of applications such as to control the transmit power of mobiles in a mobile radio communications system.

Correction of signal-to-interference ratio measurements

The present invention provides a search window delay tracking procedure for use in a multipath search processor of a CDMA radio receiver. A channel impulse response is estimated for a received signal containing plural paths, each path having a corresponding path delay. A search window defines a delay profile that contains the plural paths of the received signal. A mean or average delay is calculated for the estimated channel impulse response (CIR), and an error is determined between the mean CIR delay and a desired delay position corresponding to the center of the CIR search window. An adjustment is made to reduce that error so that the center of the search window and the mean CIR delay are aligned. The error may be processed either linearly (in one embodiment) or non-linearly (in another embodiment) to minimize the error and to reduce an influence of noise. A non-linear filtering process includes calculating a delay spread from the mean CIR delay calculated for successive processing cycles of a window delay tracking procedure corresponding to each new input. A difference is determined between the successive delay spreads. Adjustment signal is set equal to the error signal if the difference is less than or equal to a threshold. Alternatively, the adjustment signal is set to zero if the difference is greater than the threshold. Consequently, if the delay spread in the current iteration is significantly different from the delay spread in the previous iteration, the new error sample calculated in the current iteration is considered unreliable, and no adjustment is made.

Search window delay tracking in code division multiple access communication systems

(57) Abstract Optimal code sequences are generated for use in spreading and de-spreading functions in a code division multiple access (CDMA) communications system. In particular, a family of quadriphase spreading codes is employed that provides a maximal number of spreading codes to achieve a high capacity in the CDMA communications system while at the same time having a minimal peak cross-correlation between any two spreading codes within that family to ensure cross-correlation interference is kept at or below acceptable levels. That optimal quadriphase spreading code family is the S(2) family of four phase code sequences of length L = 2m-1, where m is an integer greater than or equal to 5. The size of the S(2) family of quaternary spreading codes is (L + 2)(L + 1)2, and the maximum cross-correlation is 1 + 4∑(L + 1). The spreading codes are preferably allocated to base stations using specific code subsets of the S(2) family having the same cross-correlation properties of the S(0) and/or S(1) family of codes. Spreading codes are advantageously extended by one or more code symbols as necessary or otherwise desirable. For example, to support variable transmission rate services, it is desirable to employ spreading codes whose length may be expressed as an integer multiple of each spreading factor in the mobile communications system. Since individual spreading codes have a length of 2m 1, one code symbol is added to the generated spreading code.

Branislav Popovic

Papers

Method and apparatus for efficient synchronization in spread spectrum communications

Multipath propagation delay determining means using periodically inserted pilot symbols

Correction of signal-to-interference ratio measurements

Search window delay tracking in code division multiple access communication systems

Quadriphase spreading codes in code division multiple access communications