Telefonaktiebolaget Lm Ericsson (publ)

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Roland Carlsson

Henrik Sahlin

Arne Simonsson

Ulf Gustavsson

Per Burström

Milad Fozooni

Per BURSTRÖM

A method of controlling peak-to-average power ratio (PAPR) reduction for a multi-antenna transmitter using OFDM is disclosed. Similar to tone injection, a Peak reduction signal is added to the subcarriers for suppressing peaks of the transmitted signal. However different schemes summarized on FIG.are proposed for such a superimposition of a peak reduction signal. Subcarriers carrying reference signals (DMRS) might not carry any peak reduction signal (FIG.) or at a lower power than data subcarriers (FIG.). Furthermore data subcarriers may be zeroed out to carry the peak reduction signal (resulting in tone insertion, FIG.) or the modulation order of the data subcarriers might be reduced to increase the power of the peak reduction signal.

Controlling peak-to-average power ratio reduction

A method for reducing peak-to-average power ratio, PAPR, in a Multiple Input Multiple Output, MIMO, communication system is disclosed. The method is performed in a precoder unit and includes: confining, by a differentiable cost function, power of a MIMO signal to be between a lower threshold, P, and an upper threshold, P, and applying a gradient method on the differentiable cost function until reaching a set power target for the MIMO signal, while keeping an Error Vector Magnitude, EVM, below a set EVM level.

Reducing peak-to-average power ratio in MIMO communication system

According to embodiment of the present invention, there is provided a radio base station () and a corresponding method for estimating the quality of the uplink control channel. The method comprises measuring () a quality parameter of the uplink data channel, and using () this to estimate the quality of the uplink control channel. In one embodiment, measurements of the uplink control channel are taken and their reliability determined. If the reliability is low (i.e. below a threshold, or below the respective measurements taken on the uplink data channel), then measurements on the data channel are used instead of those made on the control channel to estimate the control channel quality.

Method for estimating uplink control channel quality

An intermediary node is adapted for receiving a sequence of packets from a server, wherein the intermediary node comprises a time estimator adapted for performing the following steps&#x2014;resolving the sequence number (k) and time of arrival to the intermediary node for at least a plurality (q) of incoming packets; establishing the frame period of the incoming packets (T); establishing a sequence of normalized packet arrival times (e) as corresponding to the established frame period (T); calculating the relative arrival time (rt) of the plurality (q) of incoming packets in relation to the normalized packet arrival times; creating a cumulative density function (CDF) for a given sequence of packets; and establishing the threshold value for the relative arrival time (rt) yielding the predefined packet loss (PL) based on the cumulative density function (CDF).

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Göteborg, Sweden

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