Telefonaktiebolaget Lm Ericsson (publ)

Peter Nauclér

Henrik Sahlin

Stefan Parkvall

Johan Furuskog

Håkan Andersson

Robert Baldemair

Mattias Frenne

Martin Hessler

Jonas Fröberg Olsson

Arne Simonsson

Qiang Zhang

Chester Park

Ulf Axel Lindgren

Björn Halvarsson

The present invention relates to a user terminal, UE, in a wireless communication system (). The user terminal () comprises a receiver unit (), a transmitter unit () configured to transmit data in transmit sub-frames occurring at defined sub-frame intervals, and a control unit () configured to control the receiver circuit () and the transmitter circuit (). The control unit () is also configured to create a PRACH, Physical Random-Access Channel, preamble () as an uplink transmission to a node () that is arranged to receive communication from the user terminal in said sub-frames. This communication comprises OFDM, Orthogonal Frequency-Division Multiplexing, based symbols (). The control unit () is configured to create each PRACH preamble () such that is comprises a sequence of a plurality of identical random access sequences (s(n)), where each random access sequence (s(n)) has the same length in time as each one of the OFDM based symbols (). The present invention also relates to a corresponding method.

Enhanced PRACH preamble format

The present disclosure relates to random access in wireless communication systems, and in particular to a wireless device, a preamble receiver, and methods for processing random access preamble signals. A disclosed method in a wireless device comprises generating (S) one or more identical short sequences having a same time duration as an OFDM symbol used for carrying data traffic in a radio access network of the wireless device. The method also comprises generating (S) at least one offset indicator sequence different from each of the short sequences, and constructing (S) the preamble sequence by concatenating the at least one offset indicator sequence and the one or more identical short sequences in time, such that each of the at least one offset indicator sequence has a respective pre-determined location in the preamble sequence.

Processing of random access preamble sequences

A method performed in a preamble transmitter for transmitting a preamble sequence, the method comprising the steps of generating Sa short sequence s(n), the short sequence having the same time duration as an OFDM symbol used for carrying data traffic in a radio access network of the preamble transmitter, constructing Sa preamble sequence by concatenating a plurality of said short sequences in time, and transmitting Sthe constructed preamble sequence as a radio signal to a preamble receiver transmission and reception of a random access preamble signal.

Transmission and reception of a random access preamble signal

A network node for selecting transmission mode towards a wireless device in a wireless communications network is provided. The wireless communications network comprises a first cell and a second cell. The wireless device is connected to the first cell, which first cell is served by the network node. The network node obtains () information about respective downlink signal strength from the first cell to the wireless device, and the second cell to the wireless device. The network node selects () transmission mode towards the wireless device based on absolute signal strength and a difference in signal strength between the first cell and the second cell. The difference is calculated based on the obtained information. Publ.

Selection of transmission mode based on radio conditions

The disclosure relates to cellular radio communication systems, and especially to performing a joint reception of uplink transmissions from user equipment devices UE, UE. A serving node and a cooperating node is described together with methods performed by each node. The serving node comprises a user equipment selector, a cooperating node selector and a radio element selector. The serving node also includes a user equipment allocator, a joint reception requester configured to order joint reception data from selected cooperating nodes, and a backhaul capacity obtainer configured to obtain a backhaul capacity of selected cooperating nodes. Especially, the radio element selector is adapted to select radio resource elements based on a determined backhaul capacity. By considering the backhaul capacity, the backhaul can be employed for joint reception without becoming overloaded. The cooperating node especially includes an element prioritizing unit configured to prioritize between data obtained from different the radio resource elements.

Methods and network nodes for performing a joint reception in a cellular radio communication network

The present invention relates to a method in a receiver for decoding at least two received communication signals, wherein the communication signals are modulated, pre-coded by a discrete Fourier transform and transmitted by means of single-carrier frequency division multiple access scheme (SC-FDMA). The method comprises the steps of: performing an antenna combining and equalization on a signal observed at the receiver; performing inverse discrete Fourier transform on a model of the observed signal; whitening a time domain model of the observed signal; and jointly detecting the received at least two communication signals by performing soft value calculations based on maximum likelihood detection of a whitened time domain model using a whitened time domain channel estimate.

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Knivsta, Sweden

Peter Nauclér