Abstract: An apparatus and method for providing a security function of frames transmitted between optical network terminals (OLTs) and optical network units (ONUs) in an Ethernet passive optical network (EPON) providing media access control (MAC) services are provided.

Abstract: A multicasting system and method for use in a shared memory-based switch that includes an input subqueue reading block for reading out data inputted thereto, selecting one bit from an output port bitmap at a time and outputting output port information of one bit and class information as a data stream together with an enable signal.

Abstract: A PON slave controller for use in a PON ONU system capable of processing in unit of byte outputs an enable signal to external for a mini-slot payload and receives a byte input signal for enabling usage of an arbitrary MAC (Medium Access Control) technique loading arbitrary data in a mini-slot.

Abstract: A burst mode optical receiver includes: a photodiode which converts an input optical signal into a current signal; a pre-amplifier which converts the current signal into a voltage signal; a single-to-differential converter which converts the single voltage signal output from the pre-amplifier into differential signals; a post amplifier which amplifies the differential signals and cancels an offset occurring during the amplification or offsets inherited from the differential signals; and a discriminator which discriminates data from the differential signals.

Abstract: Provided is a burst mode optical receiver considering a characteristic of an extinction ratio of a received optical signal is provided. By using a peak detector considering a characteristic of an extinction ratio, top and bottom peak voltages of actual burst packets can be precisely detected while not being affected by a DC offset corresponding to an extinction ratio even though burst packets having a DC offset corresponding to the extinction ratio are received. Accordingly, waveform distortion of a signal output from the burst mode optical receiver can be minimized.

Abstract: Provided is a burst mode optical receiver capable of accurately detecting an optical signal of minimum amplitude, by automatically controlling a gain of a pre-amplifier according to an amplitude of an input optical signal. The burst mode optical receiver can automatically control a gain of a pre-amplifier according to the amplitude of an input optical signal using an output signal of a first peak detector. In other words, when the input optical signal has a small amplitude that meets the receiving sensitivity of the burst mode optical receiver, the gain of the pre-amplifier automatically increases, thereby improving the receiving sensitivity of the burst mode optical receiver.

Abstract: Provided are an apparatus for compensating for the characteristics of a laser diode and an optical transmitter including the apparatus. The apparatus includes: an optical output detector which detects an optical power output from the laser diode and converts the optical power into a voltage; a bias current controller which detects a maximum level of the voltage and outputs a first control value corresponding to a difference between the maximum level and a first reference voltage; a modulation current controller which detects a minimum level of the voltage and outputs a second control value corresponding to a difference between the minimum level and a second reference voltage; and a laser diode driver which outputs a drive current to the laser diode according to the first and second control values.

Abstract: A data transmission system in an EPON includes a parser classifying frames generated in each block, and transmitting the frames to a block. A scheduler performs multiplexing of frames, then, during a transmission time permitted by an OLT, determines a transmission sequence of the frames and transmits the frames. A MPCP slave processes messages transmitted from the OLT, generates response messages on the transmitted messages, and maintains time synchronization with the OLT A processor interface conveys frames transmitted from the OLT to a processor, frames primitives transmitted from the processor, and transmits the primitives to the OLT. A register stores a value used during generation of frames in each block, a value for system control, and a value acquired from MPCP control frames.

Abstract: A communication system using a layering architecture that supports peer-to-peer communication between ONUs in an Ethernet-based PON. The system includes a physical layer receiving frames from an OLT; and data link layers including an emulation layer, a MAC layer, a MAC control layer, and a MAC emulation layer. The data link layers further include a P2PE layer for generating and managing an address table that matches PON-tags of frames received from ONUs and transmission point addresses, and a mirror address table of the address table, and an FRM layer for performing, according to a target address of the frames, an upstream process that transmits frames to an upper layer and a downstream process that transmits frames to a lower layer.

Abstract: A communication node system for an Ethernet-PON includes: an LLID register for storing an LLID being an allocated identifier; a preamble generator for generating a PON preamble; a CRC generator for generating a CRC for the preamble; a transmission connector for combining transport data with the CRC-including preamble to generate a transport frame, and forwarding the transport frame; a reception connector for receiving the frame and dividing the frame into a preamble and received data; a filter for extracting an LLID from the preamble, comparing the extracted LLID with the LLID stored in the register, and selectively filtering the extracted LLID; and a received frame generator for discarding the received data, or combining the received data with the preamble to generate a received frame.

Abstract: An apparatus and method for detecting errors in received data and transferring only error-free data in data communications are provided. In the cyclic redundancy check (CRC) verification apparatus and method having a constant delay, irrespective of the length of a received data frame, input and output processing delay of received data is made to be constant. The CRC verification apparatus having constant delay comprises an input control unit which stores the start address of an input data frame in a memory storing the input data frame, and stores a CRC verification result in the start address location; and an output control unit which after a predetermined constant time passes from the start address, reads an input data frame and if the CRC verification result is normal, output the read data frame. The apparatus and method make the time taken for receiving a data frame, constant irrespective of the received data frame, while CRC verification is performed.

Abstract: A MAC master apparatus for executing a multi-point control protocol (MPCP) data in an optical line termination (OLT) of an Ethernet passive optical network (PON) is provided. The MPCP master apparatus includes a CPU interface unit, two or more memory arbitration control units, a SGA table memory, a RTT table memory, a static grant generation unit, a dynamic grant generation unit, a static grant queue, a dynamic grant queue, a sending message queue, a sending multiplexing unit, a time setting unit, a receiving window generation unit, an upstream grant queue, a received demultiplexing unit, a report queue and a received message queue. Therefore, any frame, including MPCP frames from/to the CPU can be sent or received, and a grant can be allocated statically according to a setting or dynamically according to a report from the ONUs.

Abstract: Provided is a communication apparatus in a PON bridge sublayer, which supports point-to-point communications between optical network units (ONU) in an Ethernet passive optical network (EPON). To support point-to-point communications between ONUs in the EPON, the communication apparatus in the PON bridge sublayer includes a second processing portion, a second input queue, a second lookup and learning portion, a second output queue, a first input queue, a first lookup and learning portion, a filtering database table a VLAN ID table, a table control portion, a first output queue, and a first processing portion.

Abstract: A method and apparatus for processing Ethernet data frames in a media access control (MAC) sublayer of an Ethernet passive optical network (PON) are provided.

Abstract: An apparatus and method for checking validity of an 8B/10B code-group are provided. The apparatus for checking validity of an 8B/10B code-group includes a 6B/5B disparity classification unit, a 4B/3B disparity classification unit, an RD6 detection unit, an RD4 detection unit, an 8B/10B code-group rule violation detection unit, an RD error detection unit, and a unit for outputting 8B/10B code-group validity. The apparatus receives an 8B/10B code-group, divides into a least significant 6-bit nibble and a most significant 4-bit nibble, detects a running disparity, and by doing so, determines the validity of a code-group. The apparatus and method for checking validity of an 8B/10B code-group relatively shortens the critical path, which indicates the number of combinational logic circuits that should be operated in a unit time, and therefore the apparatus and method are appropriate to high-speed systems such as gigabit Ethernet systems.

Abstract: A method of controlling data transmission in an Ethernet passive optical network (EPON) and an apparatus thereof are provided. Transmission permission messages using a mode of bandwidth allocation are queued in a queuing unit according to the types of the transmission permission messages. A transmission time duration of upstream data is defined for each of the transmission permission messages queued in the queuing unit. A bandwidth allocation unit generates transmission permission messages to allocate upstream data transmission bandwidth for an optical network unit (ONU), based on the transmission permission messages stored in the storage unit. A scheduler designates the predetermined priority, reads transmission permission messages from queues according to a predetermined priority, determines a transmission start time of upstream data, and outputs the transmission permission messages.

Abstract: A wideband multi-tone transceiver system interoperable with Asymmetric Digital Subscriber Line (ADSL) transceiver system, and including a two-step transceiver system having a discrete multi-tone transceiver system and a cosine modulated filter bank (CMFB) transmultiplexer. The two-step transceiver system provides a physically transparent transmission channel to each sub-band signal by minimizing the interference between sub-bands regardless of the transmission channel characteristics. The two-step transceiver system is realized with a comparably simple structure, and the circuit size is drastically reduced by sharing the FFT function with other sub-channels with the maximal utilization of the high-speed circuit when realizing each sub-channel's DMT modulation and demodulation function.

Abstract: Method for designing TEQs(Time-domain Equalizers) for different signal bands in a VDSL transmission system, including the steps of dividing an entire signal band into at least two signal bands, and respectively modulating the divided signal bands before transmission at a transmitter, and applying respective transmitted signal bands to an algorithm that can reduce channel response lengths of the respective signal bands at a receiver, for obtaining respective TEQs, and connecting the TEQs in series, wherein an entire signal band is divided into a low frequency signal band and a high frequency signal band, with the low frequency signal band allocated smaller than the high frequency signal band, and preferably the low frequency signal band includes the signal band used in an ADSL, whereby reducing an amount of hardware and assuring an interchangeability with the ADSL transmission system.

Abstract: An apparatus for and a method of generating pointers for identifying structure boundaries of data for leased lines such as T1/E1 in an asynchronous transfer mode (ATM) adaptation layer Type 1 (AAL1) through an ATM layer.

Abstract: Provided are an asynchronous transfer mode, passive optical network (ATM-PON) slave device and a method for transmitting data in the ATM-PON slave device. The device includes an asynchronous transfer mode, passive optical network (ATM-OPN) slave device, the device including a received frame processing unit for receiving and transmitting data; a UTOPIA receiving unit for receiving the data from the received frame receiving unit, storing the data in a FIFO queue, and transmitting the data to an ATM layer; a UTOPIA transmitting unit for receiving the data from the ATM layer, storing the data to at least two FIFO queues according to the rank of data, and transmitting the data; and a transmission frame processing unit for receiving the data from the UTOPIA transmitting unit and transmitting the data to an optical line termination (OLT). Accordingly, one optical network unit (ONU) can have a plurality of traffic containers, and a minimal modification is made to the existing G.983.