Provided is a transmission circuit with which it is possible to facilitate error correction of burst errors without increasing the processing load in multiframes configured from a plurality of OTN frame signals. This transmission circuit is provided with: a transmission-side signal recognition unit for detecting MFAS and recognizing the order of N number of OTN frame signals; an intra-multiframe sequence conversion unit for converting the sequence of data signals inside the multiframe in response to the recognized order; a transmission-side rearranging unit for consolidating the sequentially converted data signals into lengths equal to those of the OTN frame signals and creating N number of quasi-OTN frame signals; and a transmission unit for transmitting the multiframes configured from the N number of quasi-OTN frame signals.

Techniques that provide link establishment between a radio equipment controller (REC) and a radio equipment (RE) in a fronthaul network are described herein. In one embodiment, a method includes performing, Common Public Radio Interface (CPRI) Layer 1 (L1) link auto-negotiation operations to establish a CPRI link between the REC and RE. A proxy slave may achieve a hyper frame number (HFN) synchronization with the REC at a link bit rate for a first CPRI bit stream and communicate the first CPRI bit stream and the link bit rate to a proxy master. The proxy master may communicate a second CPRI bit stream to the proxy slave to transmit to the REC. The L1 link auto-negotiation operations are completed and CPRI link is established between the REC and the RE when the REC achieves a HFN synchronization for the second CPRI bit stream.

A method implemented by an optical network unit (ONU) in a passive optical network (PON). The method includes receiving an encoded downstream (DS) signal from an optical line terminal (OLT), searching for a physical synchronization sequence (PSync) pattern in all possible alignments for all possible OLT bit-interleaving modes within the downstream signal, and transitioning to a pre-synchronization state once the PSync pattern has been found.

Provided is a digital filter implementing a function by using circular convolution of a digital input signal and a unit pulse response of the digital filter in applying a filter to the digital signal. In addition, a configuration sequence change of an output signal, which occurs as a result of digital filtering according to the present invention, in comparison to an input signal, is corrected by inversely performing circular shifting in a transmitter by amount of the configuration sequence change, or by reconstructing a signal after making synchronization and acquiring the signal previous to a time point of the synchronization by amount of the configuration sequence change, in a receiver.

A transmission apparatus includes: a first mapping unit configured to allocate a first frame that stores a client signal to an intermediate frame; a second mapping unit configured to allocate the intermediate frame to a second frame that has a higher bit rate than a bit rate of the first frame; and a rate controller configured to control a bit rate of the intermediate frame based on the bit rate of the first frame and the bit rate of the second frame.

Techniques that provide link establishment between a radio equipment controller (REC) and a radio equipment (RE) in a fronthaul network are described herein. In one embodiment, a method includes performing, Common Public Radio Interface (CPRI) Layer 1 (L1) link auto-negotiation operations to establish a CPRI link between the REC and RE. A proxy slave may achieve a hyper frame number (HFN) synchronization with the REC at a link bit rate for a first CPRI bit stream and communicate the first CPRI bit stream and the link bit rate to a proxy master. The proxy master may communicate a second CPRI bit stream to the proxy slave to transmit to the REC. The L1 link auto-negotiation operations are completed and CPRI link is established between the REC and the RE when the REC achieves a HFN synchronization for the second CPRI bit stream.

This application provides a synchronization signal transmission method and a communications apparatus. The synchronization signal transmission method and the communications apparatus are applied to the communications field. In the synchronization signal transmission method, a synchronization signal generated and sent by a network device may include a first sequence and a second sequence. The first sequence is a first complex sequence or a sequence obtained based on the first complex sequence. The second sequence is a sequence obtained based on the first complex sequence, and the second sequence is different from the first sequence. Because a correlation processing result between the first sequence and the second sequence is still a complex sequence, there is a good correlation property, so that a terminal device can obtain a relatively sharp correlation peak when synchronizing with the network device based on the synchronization signal, thereby effectively shortening duration required for synchronization.

Techniques that provide link auto-negotiation between a radio equipment controller (REC) and a radio equipment (RE) are described herein. In one embodiment, a method includes performing, by a proxy master, a Common Public Radio Interface (CPRI) Layer 1 (L1) link auto-negotiation with a RE to achieve a L1 synchronization between the proxy master and the RE at a link bit rate; communicating the link bit rate from the proxy master to a proxy slave; performing, by the proxy slave, a CPRI L1 link auto-negotiation with a REC to determine whether a L1 synchronization between the proxy slave and the REC is achieved, wherein if the L1 synchronization is achieved, the link bit rate is a common matching link bit rate achieved; and upon the common matching link bit rate being achieved, establishing a CPRI link between the REC and the RE using the common matching link bit rate.

Techniques that provide link auto-negotiation between a radio equipment controller (REC) and a radio equipment (RE) are described herein. In one embodiment, a method includes performing, by a proxy master, a Common Public Radio Interface (CPRI) Layer 1 (L1) link auto-negotiation with a RE to achieve a L1 synchronization between the proxy master and the RE at a link bit rate; communicating the link bit rate from the proxy master to a proxy slave; performing, by the proxy slave, a CPRI L1 link auto-negotiation with a REC to determine whether a L1 synchronization between the proxy slave and the REC is achieved, wherein if the L1 synchronization is achieved, the link bit rate is a common matching link bit rate achieved; and upon the common matching link bit rate being achieved, establishing a CPRI link between the REC and the RE using the common matching link bit rate.

The present disclosure relates to a method for determining an availability of a synchronization source in a communication system. The method comprises: detecting a stability of the synchronization source when the synchronization source recovers from a failure; and determining the availability of a synchronization source based on the detected stability of the synchronization source. The present disclosure also relates to network devices and a computer readable medium for performing said method.