Telefonaktiebolaget Lm Ericsson (Publ)

Unwired Planet, LLC

Bo Gosta Hedberg

Magnus C Frodigh

Ulf Skärby

Alex K Raith

Georg Frank

Carl Magnus Frodigh

Christer Johansson

Yngve Kenneth Wallstedt

Peter M Petersson

Tomas Stolt

Par S Bergsten

Christian Nystr&ouml;m

Bo Hermansson

Jan-Erik Stiernvall

Carl Fredric Kronestedt

John Tomas Dannelind

Patrick Eriksson

Anders Borje Forsen

A modulation method for data packets transmitted on a mobile communication channel, the method comprising a first linear modulation mode, to be used when the radio conditions are good, and a second constant envelop modulation mode, to be used when the radio conditions are poor. Since a constant envelope-modulated signal is degraded more when time dispersion occurs, the first linear modulation mode is also used when the time dispersion is severe.

Adaptive modulation scheme for multipath wireless channels

A method, device and system for reducing the number of feeders () between a radio base station () and an antenna diversity arrangement () at which RF signals of the same frequency are received. In a tower mounted amplifier () individual RF signals from some or all of the antennas are frequency converted into intermediate frequency (IF) signals on mutually different intermediate frequencies which are combined and forwarded to the radio base station on a reduced number of feeders. In the radio base station the combined signal is split into individual signals amongst which the IF signals are frequency transformed to a signal suitable for diversity processing.

Method device base station and site for reducing the number of feeders in an antenna diversity diversity system

A transmit power control system and method is provided which utilizes an efficient allocation of average output power of a multi-carrier power amplifier (MCPA), the average output power being a weighted average of the actual power over multiple time slots. Periodically, using the efficient allocation system and method, there will be short periods where the desired average output power will exceed the maximum tolerable power of the MCPA, P . These short periods in which the desired output power will exceed P are handled by a system and method which produces a reduced margin between the total power per time slot and P This reduced margin allows the MCPA to serve a larger number of users per time slot than conventional MCPAs. Alternatively, the MCPA can serve the same number of users as a conventional MCPA, but with higher demands on output power for each user and/or more efficient use of the MCPA's resources.

Transmit power control for MCPA-equipped based stations

In a telecommunications network that employs a CDMA scheme, the amplitude associated with each independent CDMA carrier is digitally limited, thereby limiting the peak-to-average power ratio. This, in turn, is accomplished by measuring the instantaneous amplitude for the in-phase and quadrature signals that make up each CDMA carrier, deriving a maximum amplitude based on the instantaneous amplitude measurements, and then deriving one or more scaling factors based, in-part, on maximum amplitude. The one or more scaling factors are then applied to the in-phase and quadrature signals, which are subsequently filtered, combined and modulated by a corresponding CDMA carrier frequency.

Amplitude limitation in CDMA system

A communication network, and associated method, permitting wireless communication with a mobile unit in an indoor environment. Transceivers are positioned at spaced-apart locations and are coupled to a centralized, control device. The transceivers include transmitter portions and wideband receiver portions. Uplink signals transmitted by a mobile unit are received by receiver portions of transceivers within the range of the uplink signal. Downlink signals are generated by at least two transmitter portions of at least two transceivers. The control device controls selection of which transmitter portions and which receiver portions of the plurality of transceivers are utilized to effectuate two-way communication with the mobile unit. Control signals can also be transmitted by the transmitter portions of all of the transceivers such that a mobile unit positioned anywhere within the area of the communication network receives the control signals.

Distributed indoor digital multiple-access cellular telephone system

A system for transmission of combined, multi-carrier signals wherein combiner/filters, commonly called combiners, have been eliminated. A cartesian feedback loop linearizes the system and thereby suppresses carrier frequency intermodulation by feeding back a portion of the combined multi-carrier signal to each channel device.

Cartesian multicarrier feedback

A phase locked loop frequency synthesizer in which the output frequency is changed in a series of steps in order to reach a final frequency value. The steps are computed and stored in a memory in a control unit. The steps are chosen to approximately cancel the poles of the transfer function of the synthesizer. The phase locked loop provides increased switching speed.

Step controlled signal generator

Apparatus for correcting the frequency in a coherent receiver associated with a radio communication installation, e.g. a mobile telephone installation for transmitting digital information in time-division multiplex. The receiver includes a controllable local oscillator (7) for generating a mixing signal for converting the frequency of a received signal, and unit (4,8,9) for calculating a frequency error and generating a control signal (f') to the oscillator (7). Each new value of the control signal (f') is dependent on a previous value and on the calculated frequency error, and is utilized for correcting the frequency of said mixing signal. At least the major part of a frequency error in the receiver is thus eliminated. A possibly remaining part of a required frequency correction is carried out by a frequency change in the baseband. This is achieved with the aid of a unit (11) included in the receiver, and adapted to perform regularly repeated phase shifts of a signal (I,Q) in the baseband by a value (V.sub.r), which is changed for each received modulation symbol, e.g. a data bit, and which is responsive to said remaining part of the required frequency correction.

Apparatus for correcting frequency in a coherent receiver

An arrangement for compensating errors occurent in a quadrature modulator. Two quadrature signals (cos a(t), sin a(t)) in the baseband are generated, each of which signals is delivered to a respective branch in the modulator two high frequency signals (cos wt, sin wt) with a mutual phase difference of 90 degrees are generated and mixed with the quadrature signals (cos a(t), sin a(t)) and an adder (5) produces the sum of the output signals of the mixers (3, 4). Amplitude errors and phase errors are compensated with the aid of a separate compensating network (11, 12, 14, 16, 17, 19, 21) which is incorporated in the low frequency part of the modulator and which includes adjustable signal generator (14, 16). Local oscillator leakage is compensated with the aid of a second compensating network (13, 15, 18, 20) which is also incorporated in the low frequency part of the modulator and which also includes an adjustable signal generator (15, 18). The signals (k4, k5) from the latter generator (15, 18) are subtracted from the signals occuring in the two branches of the modulator.

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Kista, Sweden

Bo Gosta Hedberg