Telefonaktiebolaget Lm Ericsson (publ)

Unwired Planet, LLC

Afif Osseiran

Andrew Logothetis

Jawad Manssour

Muhammad Ali Kazmi

Stefan Wager

Qingyu Miao

Johan Torsner

Janne Peisa

Zhang Zhang

Jiann-Ching Guey

Rong Hu

Jiansong Gan

Mats Fredrik Sägfors

Ben Slimane

Slimane Ben Slimane

Embodiments herein relate to a method performed by a relay node for relaying user data from/to one or more communication devices to/from a radio access node in a wireless communication network. The relay node receives a first user data stream in a first time slot and/or a second user data stream in a second time slot from a first communication device and a second communication device respectively, or from the radio access node. The relay node independently applies a network coding on the received first and/or second user data streams. The relay node forwards the network coded first user data stream in a third time slot to the radio access node or the first communication device, and/or the second user data stream in another time slot to the radio access node or the second communication device.

Radio access node, relay node and methods performed therein

A data communication involves selecting a group () of M multiple source nodes () among N multiple source nodes () present in a communication system () and having data destined for a destination node (), where 2&#x2266;M&#x3c;N. A relay node () network codes data from the selected group () of M nodes () to form combined, network coded data. This resulting data is sent to towards the destination node (). The purposeful selection of source nodes () in connection with network coding substantially increases the throughput of the communication system ().

Network coded data communication

A method and arrangement for retransmission control. A method in a sending system entity for controlling retransmissions of data to a sending system entity is provided. Initial data encoded with a first forward error correction code is sentto the receiving system entity. When transmitted initial data is determined to be affected by errors at the receiving system entity, the sending system entity receivesa request to retransmit the initial data combinedby new data encoded with a second forward error correction code in a combined data stream which is encodedwith a third forward error correction code before being sentto the receiving system entity. By combining initial data and encoded new data in a combined data stream when resending, an effective and flexible procedure for retransmissions is achieved, which doesn't introduce any substantial delay of the data.

Method and arrangement for retransmission control

A communication unit for use in a wireless communication system in which a transmitting unit is arranged for wireless communication with at least one receiving unit, said network further comprising at least a first and a second relay node arranged to receive a signal from the transmitting unit and forward it to the receiving unit, said node being characterized in that it comprises a processor arranged to perform the following steps: identifying at least a first and a second communication path between the transmitting unit and the receiving unit, at least one of said paths involving the first or the second relay node, calculating a first and a second capacity of at least one hop in the first and second communication path, respectively communicating information related to the first and second capacity to at least one other communication node in the wireless network.

Communication unit and a method in a wireless communication network

A base station in a wireless network receives link quality data from multiple relay nodes that relay data from the user terminals to the base station and/or from user terminals. The base station applies one or more cost functions to the link quality data and selects a relay node from the multiple relay nodes for network coding of data from a group of the user terminals based on results of the one or more cost functions. The base station notifies the selected relay node to network code data from the group of user terminals.

Relay node selection for network coding

A base station serves multiple user terminals via a relay node in a cell of a wireless network. The base station includes a time division scheme selection unit that selects a time division scheme from multiple time division schemes that optimizes a parameter associated with network coding of data transmitted between the multiple user terminals and the base station via the relay node. The base station further includes a transmission allocation unit that allocates uplink and/or downlink transmission intervals and interval lengths, based on the selected time division scheme, to each of the multiple user terminals and to the relay node. The base station also includes a notification message unit that notifies the multiple user terminals and the relay node of their respective transmission interval and interval length allocation.

Relative time division for network coding

A radio channel estimation technique is described for use in a OFDM-based radio communications system. A block of OFDM symbols is transmitted from multiple antennas over multiple sub-carrier frequencies. The block of OFDM symbols includes known pilot symbols as well as data symbols to be determined by a receiver. The pilot symbols are transmitted in a predetermined pattern at periodic times on periodic sub-carriers. A pilot channel estimate is determined for each pilot symbol in the received block of OFDM symbols. An N&#xd7;M matrix of points corresponding to the received OFDM symbol block is formed. N is the number of sub-carriers and M is the number of OFDM symbols in the OFDM symbol block. The matrix is formed by inserting pilot channel estimates at predetermined positions in the N&#xd7;M matrix according to the predetermined pilot pattern and inserting zeros in remaining positions in the N&#xd7;M matrix. A two dimensional inverse Fourier transform of the N&#xd7;M matrix is calculated resulting in multiple copies of a channel estimate in the time domain. One is selected, and a two dimensional Fourier transform of the selected channel estimate is calculated to obtain a channel estimate at each point in the OFDM block.

Time and frequency channel estimation

A method for transmitting data flows between a network element and a number of receivers over a first channel. The method comprises the steps of: performing a link adaptation for the transmission of a data flow by said network element, and transmitting the data flow, transmitting an indication of a channel quality required for reception of the data flow on a second channel, receiving by said receivers said indication of channel quality, measuring a link quality by said receivers by monitoring a pilot channel, comparing said measured link quality with said received indication of the channel quality, and transmitting to said network element result of said comparison of said measured link quality with said received indication of the channel quality, if said result is lower than a predetermined value. The invention also relates to a network element and a user equipment.

Method and arrangement for transmitting CQI on the uplink

A radio channel estimation technique is described for use in a OFDM-based radio communications system. A block of OFDM symbols is transmitted from multiple antennas over multiple sub-carrier frequencies. The block of OFDM symbols includes known pilot symbols as well as data symbols to be determined by a receiver. The pilot symbols are transmitted in a predetermined pattern at periodic times on periodic sub-carriers. A pilot channel estimate is determined for each pilot symbol in the received block of OFDM symbols. AnM matrix of points corresponding to the received OFDM symbol block is formed.is the number of sub-carriers andis the number of OFDM symbols in the OFDM symbol block. The matrix is formed by inserting pilot channel estimates at predetermined positions in thematrix according to the predetermined pilot pattern and inserting zeros in remaining positions in thematrix. A two dimensional inverse Fourier transform of thematrix is calculated resulting in multiple copies of a channel estimate in the time domain. One is selected, and a two dimensional Fourier transform of the selected channel estimate is calculated to obtain a channel estimate at each point in the OFDM block.

A wireless communication system uses relaying to enhance performance. Artificial frequency selectivity and spatial diversity are provided by introducing delay diversity. A transformed OFDM chunk is subjected to a 2D cyclic prefix by pre-appending to a representation of the chunk the last column of the representation and by copying a number of the last rows of the pre-appended chunk to the top of the representation thereby forming an augmented OFDM chunk.

Method and arrangement in wireless communication networks using relaying

According to one embodiment, a wireless communication device estimates channel response based on a reduced-density common pilot signal comprising a plurality of regularly spaced common pilot symbols when the reduced-density common pilot signal is sufficient for estimating the channel response with a desired accuracy. The wireless communication device estimates the channel response based on the reduced-density common pilot signal and one or more additional pilot symbols adaptively allocated to the wireless communication device when the reduced-density common pilot signal is insufficient for estimating the channel response with the desired accuracy.

Adaptive pilot symbol allocation method and apparatus

A radio base station includes multiple antennas associated with a cell. Multiple mobile radios are selected to receive transmissions over a shared radio channel during a predetermined time interval. Information is transmitted over the shared radio channel to multiple mobile radios in the cell during the predetermined time interval using multiple antenna beams. As a result, interference from the transmission appears as white additive Gaussian noise in time and in space in the cell. A 'flashlight effect' caused by a single beam transmission over the shared channel during a predetermined time interval that would normally detrimentally impact mobile channel quality detection is avoided. Other methods for avoiding the flashlight effect are described.

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Afif Osseiran