WO2007102302A1

WO2007102302A1 - Station apparatus and pon system uplink communication method

Info

Publication number: WO2007102302A1
Application number: PCT/JP2007/052948
Authority: WO
Inventors: Hiroshi Murata
Original assignee: Sumitomo Electric Industries, Ltd.
Priority date: 2006-03-06
Filing date: 2007-02-19
Publication date: 2007-09-13
Also published as: JP2007243285A

Abstract

A PON system composed of a terminal connected through an optical fiber (5) and a station apparatus (1) for managing the terminal. A control signal processing section (104) gives the terminal a grant of uplink communication. A next-reception burst judging section (106) stores the rate of transmission of a plurality of uplinks used by the terminal and specifies the time at which the next uplink signal is received under the grant and the transmission rate. A light-receiving section (109) and a PON receiving section (107) associate the reception function with the specified transmission rate in concert with the time, and thus the signal is received in this state.

Description

Specification

Station side apparatus and upstream communication method of PON system

Technical field

The present invention relates to a PON (Passive Optic Network) system that connects a station-side device and a plurality of terminal devices via an optical fiber network, and in particular, the terminal device power also relates to uplink communication to the station-side device.

Background art

[0002] In a PON system, a station-side device as an aggregation station and a terminal device installed in a plurality of subscriber houses are optically branched from a single optical fiber to a plurality of optical fibers via a light power bra. They are connected by a fiber network (for example, see Japanese Patent Laid-Open No. 2004-64749 (FIG. 4) and Japanese Patent Laid-Open No. 2004-289780 (FIG. 31);). Upstream burst communication from the terminal device to the station side device is managed in a time-sharing manner by the station side device that prevents signal collision.

[0003] Initially, strong burst communication was thought of at a constant transmission rate. From now on, a stepwise high-speed transmission rate is expected. However, even if high-speed transmission rate service provision starts, not all subscribers want it at the same time, so there is an existing transmission rate and a high-speed transmission rate exceeding that for uplink communication. Thus, a multi-rate PON system coexists in one PON system (see, for example, JP-A-8-8954 (FIG. 2)).

[0004] In the multi-rate PON system as described above, a reception function corresponding to a plurality of types of transmission rates is required for the station side device. However, it is not technically easy to start receiving a burst signal from each terminal device, detect its transmission rate, and synchronize the reception function to the transmission rate at high speed. In addition, an expensive PON receiver is required. Further, since effective data communication cannot be performed within the time until synchronization is established, the longer the time, the worse the efficiency of uplink communication.

Disclosure of the invention

[0005] In view of the prominent problems, the present invention provides a PO having a plurality of types of uplink transmission rates of a terminal device. It is an object of the present invention to provide a station-side apparatus and an upstream communication method for a PON system that can easily and quickly establish synchronization with an upstream transmission rate in an N system.

[0006] The present invention is a station-side device that configures a PON system together with a terminal device connected via an optical fiber and manages the terminal device, and a plurality of types of uplinks used by the terminal device. Management means for storing a transmission rate, giving the terminal device a communication overhead uplink, and specifying a next transmission timing and a transmission rate based on the grant. In addition, according to the above-mentioned period, the reception function is provided with a reception unit that corresponds to a specified transmission rate.

[0007] Based on the grant given to the terminal device, the station side device configured as described above obtains information on the next time to receive an uplink signal and its transmission rate before actual reception. Can do. In addition, if a signal is received with the reception function corresponding to the transmission rate, synchronization can be quickly established. Therefore, it is possible to easily and quickly establish synchronization with the transmission rate of the uplink communication and increase the efficiency of the uplink communication.

[0008] Further, in the station side device, the management means further specifies the type of the sign of the uplink signal in addition to the transmission rate, and the reception means receives the signal in accordance with the time. It is also possible to make the function correspond to the specified code type!

In this case, based on the grant given to the terminal device, it is possible to know the type of sign of the uplink signal to be received next before actual reception. In addition, if a signal is received with the reception function corresponding to the type of encoding, decoding can be performed quickly. Furthermore, if the encoded code is an error correction code, the distance that can be transmitted with the same transmission power can be extended with respect to the optical transmission power of the terminal device.

[0009] Further, in the station-side apparatus, the management means further specifies the type of the encryption signal of the uplink signal in addition to the transmission rate, and the reception means receives the reception function according to the time. Can be made to correspond to the specified type of encryption key.

In this case, based on the grant given to the terminal device, it is possible to know the type of encryption signal of the uplink signal to be received next before actual reception. In addition, if a signal is received with the reception function corresponding to the type of encryption key, the decryption can be performed quickly. Therefore, the confidentiality of communication with a specific terminal device can be improved. [0010] Further, the present invention is an upstream communication method of a PON system in which a terminal device that uses a plurality of types of upstream transmission rates and a station side device that manages the terminal device are connected via an optical fiber. And storing a plurality of types of uplink transmission rates used by the terminal apparatus, giving an uplink communication grant to the terminal apparatus, and then, based on the grant, an uplink signal The reception time and the transmission rate are specified, and the reception function is made to correspond to the specified transmission rate according to the time.

[0011] In the uplink communication method of the PON system as described above, based on the grant given to the terminal device, information on the next uplink signal reception timing and its transmission rate is obtained before actual reception. Can do. In addition, if a signal is received with the reception function corresponding to the transmission rate, synchronization can be quickly established. Therefore, it is possible to easily and quickly establish synchronization with the transmission rate of the uplink communication, thereby increasing the efficiency of the uplink communication.

Brief Description of Drawings

FIG. 1 is a connection diagram of a PON system according to an embodiment of the present invention.

2 is a block diagram showing an outline of the internal configuration of the station side device in the PON system of FIG.

FIG. 3 is a block diagram showing an outline of the internal configuration of one terminal device in the PON system of FIG. 1.

FIG. 4 is a block diagram showing an outline of the internal configuration of another terminal device in the PON system of FIG. 1.

FIG. 5 is a sequence diagram showing an operation between the station side device and the terminal device.

FIG. 6 is a sequence diagram showing transmission and reception related to bandwidth allocation to a terminal device and uplink communication between the station side device and the terminal device.

[FIG. 7] A diagram showing a deskew process performed between a station-side device and an unregistered terminal device.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a connection diagram of a PON system according to an embodiment of the present invention. In the figure, a station side device 1 is installed as a central station for a plurality of terminal devices 2-4. Terminal device 2 ~ Each 4 is installed at the PON system subscriber's home. An optical fiber network (5 to 9) is configured in which a single optical fiber 5 connected to the station side device 1 is branched into a plurality of optical fibers (branch lines) 7 to 9 through a light force bra 6. Terminal devices 2 to 4 are connected to the ends of the branched optical fibers 7 to 9, respectively. Further, the station side device 1 is connected to the host network 11 and the terminal devices 2 to 4 are connected to the respective user networks 12 to 14.

In FIG. 1, three terminal devices 2 to 4 are shown, but it is possible to connect 32 terminal devices by branching, for example, 32 from one optical power plastic 6. In FIG. 1, only one optical power bra 6 is used, but more terminal devices can be connected to the station side device 1 by providing a plurality of optical power bras in a column.

In FIG. 1, data is transmitted with a wavelength in the upstream direction from each terminal device 2 to 4 to the station side device 1. Conversely, in the downstream direction from the station side device 1 to the terminal devices 2 to 4, the wavelength is detuned.

2 data is sent. These wavelength lengths are in accordance with IEEE Standard 802.3ah—2004 Cla.

1 2

Based on use60! /, the values can be in the following ranges.

1260nm≤ λ≤1360nm

1480nm≤ λ≤1500nm

2

[0016] Also, the transmission rates of uplink communication in the terminal devices 2, 3, and 4 are L [Gbps], M [Gbps], and H [Gbps], respectively. Here, the values of L, M, and H are in a relationship of L <M <H. For example, L = l, M = 2, and H = 10. On the other hand, the transmission rate of the downlink communication in the station side device 1 is one type of D [Gbps], and the value of D is 1, for example.

In this example, three terminal devices are used, and three different transmission rates are used. However, the number of terminal devices and the number of different transmission rates may vary.

FIG. 2 is a block diagram showing an outline of the internal configuration of the station-side device 1. Each unit (101 to 115) in the station side device 1 is connected as shown in the figure. In the figure, the frame from the upper network 11 is received by the upper network side receiving unit 101 and sent to the data relay processing unit 103. The data relay processing unit 104 passes the frame to the PON side transmission unit 105, and the optical transmission unit 108 converts the wavelength into an optical signal having a transmission rate of D [Gbps].

2

Then, it is sent to the terminal devices 2 to 4 via the multiplexing / demultiplexing unit 110.

On the other hand, optical signals (wavelength, transmission rate) transmitted in the upstream direction from terminal apparatuses 2 to 4 (FIG. 1). (LZMZH [Gbps]) passes through the multiplexing / demultiplexing unit 110 and is received by the optical receiving unit 109. The optical receiving unit 109 includes a photoelectric conversion element 111 and an amplifier 112 inside. The photoelectric conversion element 111 is a semiconductor light receiving element such as a photodiode or an avalanche photodiode, and outputs an electrical signal corresponding to the amount of light received. The amplifier 112 amplifies and outputs the electric signal. The output signal of the amplifier 112 is input to the PON side receiving unit 107.

The PON side receiving unit 107 includes a clock data reproducing unit 113, a physical layer encoding / Z decoding unit 114, and a frame reproducing unit 115. The clock data recovery unit 113 recovers the timing component (clock) and data in synchronization with the electrical signal received from the amplifier 112. The physical layer encoding Z decoding unit 114 decodes the code applied to the reproduced data. The frame reproduction unit 115 also detects the boundary of the frame with the decoded data force, for example, restores an Ethernet (registered trademark) frame. In addition, the frame playback unit 115 determines whether the received frame is a data frame or a frame of control information for media access control such as a report frame by reading the header portion of the frame.

[0020] As an example of the control information, an MPCP (Multi-point Control Protocol) PDU (Protocol Data Unit) described in Clause 64 of IEEE Standard 802.3ah-2004 can be cited. The station side device 1 grants control information grants to the terminal devices 2 to 4 to instruct the uplink data transmission start time and transmission permission amount, and the terminal devices 2 to 4 A report, which is control information for notifying a value related to the amount of accumulated direction data, is a kind of MPCP PDU.

If the result of the determination is that the frame is a data frame, the frame playback unit 115 sends this to the data relay processing unit 103. The data relay processing unit 103 performs predetermined relay processing such as transmission control for the higher-layer network side transmission unit 102 by changing the header information of the data frame, and the processed frame is transferred from the higher-level network side transmission unit 102 to the higher-level network 11. Sent out. If the result of the determination is that the frame is a report frame, the frame playback unit 115 sends it to the control signal processing unit 104. Based on this report, the control signal processing unit 104 generates a grant frame as control information, which is transmitted from the PON-side transmission unit 105 and the optical transmission unit 108 via the multiplexing / demultiplexing unit 110 for wavelength transmission and transmission. Rate D [Gbps], downlink Sent in the direction.

[0022] The grant is also sent to the next reception burst determination unit 106. The next reception burst determination unit 106 stores the transmission rate used by the terminal apparatuses 2 to 4, and specifies the next burst signal reception timing and the transmission rate based on the grant. Then, the specified transmission rate is notified to the optical receiver 109 and the PON side receiver 107. The optical reception unit 109 and the PON side reception unit 107 can make the reception function correspond to the specified transmission rate in accordance with the timing.

[0023] Specifically, the multiplication factor of the photoelectric conversion element 111 in the optical receiving unit 109, the gain of the amplifier 112, the quantization determination threshold value in the PON side receiving unit 107, the lock allowable range in the clock / data reproducing unit 113, reference By switching the circuit parameters related to burst reception, such as the clock frequency, the system can be configured to support a predetermined transmission rate. For example, when the terminal devices 2 to 4 are connected under the same line conditions (the same optical power budget is the same), and transmission quality with the same bit error rate must be satisfied. When receiving from the terminal device 4 having a higher transmission rate compared to the terminal devices 2 and 3, the gain of the optical receiving unit 109 is lowered to widen the band.

[0024] For example, when the terminal devices 2 and 4 perform burst communication in the upstream direction at 1.25 Gbps and 10. 3125 Gbps, respectively, the transmission rate of the next burst is lGbps in advance with respect to the clock data recovery unit 113, respectively. Therefore, if it is notified that it is lOGbps, then it is only necessary to add the fractions, so that the synchronization of the clock data recovery unit 113 can be established reliably in a short time. Furthermore, if it is assumed that physical layer code 匕 Z decoding 匕 is performed with 8BZ10B code and 64BZ66B code for 1.25 Gbps and 10.3125 Gbps, respectively, decoding to be used for the next burst A simple circuit can be selected easily and reliably.

FIG. 3 is a block diagram illustrating an outline of the internal configuration of the terminal device 2, and each unit (201 to 209) in the terminal device 2 is connected as illustrated. In FIG. 3, an optical signal transmitted in a downstream direction from the station side device 1 (FIG. 1) passes through the multiplexing / demultiplexing unit 201 and is converted into an electrical signal by the optical receiving unit 202. Is received by the PON side receiving unit 204. [0026] The PON-side receiving unit 204 reads the header portion (including the preamble portion) of the received frame, so that the frame is addressed to itself (in this case, the device in the user network 12 itself or its subordinates). It means whether or not. If the result of the determination is that it is addressed to itself, the corresponding frame is fetched. Otherwise, the corresponding frame is discarded. For example, a logical link identifier (LLID) described in IEEE standard 802.3ah-2004 can be given as an example of header information for performing the above destination determination.

[0027] Further, the PON side receiving unit 204 determines whether the received frame is a data frame or a grant frame by reading the header portion of the frame. As a result of the determination, if it is a data frame, the PON side receiving unit 204 sends this to the data relay processing unit 207. The data relay processing unit 207 performs predetermined relay processing such as transmission control for the user network side transmission unit 208, and the processed frame is transmitted from the user network side transmission unit 208 to the user network 12.

If the frame is a grant frame as a result of the determination, the PON side receiving unit 204 transfers this to the control signal processing unit 206. The control signal processing unit 206 instructs the data relay processing unit 207 to perform uplink transmission based on the grant frame.

On the other hand, a frame from the user network 12 is received by the user network side receiving unit 209 and transferred to the data relay processing unit 207. The transferred frame is stored in the buffer memory in the data relay processing unit 207 and the data amount is notified to the control signal processing unit 206. The control signal processing unit 206 controls transmission to the PON side transmission unit 205, and at a predetermined timing, causes the PON side transmission unit 205 to output the frames accumulated in the buffer memory and also notifies the notified buffer. A report frame is created based on the amount of data stored in the memory and output to the PON side transmission unit 205. The output of the PON side transmission unit 203 is converted into an optical signal by the optical transmission unit 203, and is transmitted in the upstream direction through the multiplexing / demultiplexing unit 201 as a signal having a wavelength and a transmission rate L [Gbps].

FIG. 4 is a block diagram showing an outline of the internal configuration of the terminal device 4 (transmission rate H [Gbps]). Each unit (401 to 411) in the terminal device 4 is shown in FIG. So that it is connected. Among these, 401 to 409 are circuit elements corresponding to 201 to 209 in FIG. 3, and have similar functions. The difference from FIG. 3 is that between the control signal processor 406 and the optical receiver 403 A recording request transmission unit 411, a point that the PON side transmission unit 405 and the registration request transmission unit 411 can be switched by the transmission unit switching determination unit 410, and the transmission unit switching determination unit 410 is a point where the transmission unit is switched in response to a command from the control signal processing unit 406.

[0031] Normally, the PON side transmission unit 405 operates as the transmission unit. Note that the terminal device 14 when the PON side transmitting unit 405 operates is substantially the same as the terminal device 12.

Further, the apparent configuration of the terminal device 3 is the same as that in FIG. However, as described above, the transmission rate of the terminal device 3 is M [Gbps], which is different from that of the terminal device 4.

Next, the operation procedure in the PON system configured as described above will be described with reference to the sequence diagram of FIG. This sequence diagram is for the operation between the station side device 1 and the terminal device 2, but the same applies to the other terminal devices 3 and 4.

In FIG. 5, the station apparatus 1 has already calculated an RTT (Round Trip Time) related to the terminal apparatus 2 at the time of the operation time start time TO. At time Tal, the station apparatus 1 transmits a grant (grant frame) G1 including a report transmission start time Tb2 to the terminal apparatus 2 in order to notify the transmission request amount. This report transmission start time Tb2 is calculated so as not to collide with reports transmitted from other terminal apparatuses 3 and 4.

[0034] When terminal device 2 receives grant G1 for itself, terminal device 2 refers to the amount of data stored in the buffer memory of data relay processing unit 207 to calculate a transmission request amount, and starts transmitting a report included in grant G1. At time Tb2, a report (report frame) R1 including the requested transmission amount is transmitted to the station side device 1.

[0035] When the station side device 1 receives the report R1, the value is equal to or less than the fixed or variable maximum transmission permission amount and can transmit as much data as the amount of data in the buffer memory included in the report R1. And the calculation result is inserted into grant G2 as the permitted transmission amount. When the transmission request amount included in the report R1 is zero, the calculation result by the station side device 1 becomes zero, so no bandwidth is allocated, but since the terminal device 2 needs to send the report R2, Station-side device 1 always sends grant G2 to terminal device 2.

[0036] The transmission start time Tb4 included in the grant G2 is the previously calculated terminal device data. Data and reports from other terminal devices 3 and 4, using the scheduled reception time of the data, the previous transmission allowance of the terminal device 2, the RTT for the current terminal device 2 and the guard time that is a fixed time. Is calculated so as not to collide with. The station-side device 1 calculates a time Ta3 at which the grant G2 including the permitted transmission amount and the transmission start time Tb4 is transmitted so that the grant G2 arrives at the terminal device 2 by the transmission start time Tb4.

[0037] When the terminal device 2 receives the grant G2 for itself, the terminal device 2 transmits the data D for the permitted transmission amount together with the report R2 including the next requested transmission amount at the transmission start time Tb4 included in the grant G2. Send to 1. This report R2 is sent immediately before or after data D. If it is sent immediately before data D, the value to be reported to the station side device 1 as the send request amount is stored in the nota memory. This is the difference between the amount of data and the amount of data D.

[0038] Upon receiving the data D and the report R2, the station side device 1 transmits the data D to the upper network 11 and performs the same process as the process for the report R1! The sequence processing described above is performed independently for all the terminal devices 2 to 4, and the processing from time Ta3 to time Ta4 is repeated until the operation time ends.

[0039] FIG. 6 is a sequence diagram showing bandwidth allocation to the terminal devices 2 to 4 and transmission / reception related to uplink communication between the station side device 1 and the terminal devices 2 to 4. An example of the distributed allocation method is shown in FIG. Show. The operation of the system will be described with the station side device 1 as the subject, assuming that time progresses from the left side to the right side of the figure.

[0040] First, the station-side device 1 sequentially sends grants G41, G31, and G21 to the terminal devices 4, 3, and 2, respectively. When receiving the reports R41, R31, and R21 from the terminal devices 4, 3, and 2, the station side device 1 first sends a grant G42 to the terminal device 4 that is permitted to send data.

[0041] The station side device 1 receives the data D41 sent from the terminal device 4 and the next report R42, and at the same time sends the grant G32 to the terminal device 3. The station-side device 1 receives the data D31 sent from the terminal device 3 and the next report R32, and sends a grant G22 to the terminal device 2 in parallel therewith. Subsequently, the grant G43 for the terminal device 4 is also transmitted. [0042] The station side device 1 receives the data D21 and the next report R22 transmitted from the terminal device 2. Further, the station side device 1 receives the data D42 sent from the terminal device 4 and the next report R43, and at the same time, sends a grant G33 to the terminal device 3. Furthermore, the station side apparatus 1 receives the data D32 sent from the terminal apparatus 3 and the next report R33, and at the same time, sends a grant G23 to the terminal apparatus 2. Here, if there is no data transmitted from the terminal device 2, the station side device 1 receives only the next report R23. Thereafter, the same processing is repeated, and the station side device 1 sequentially allocates bands to the terminal devices 2 to 4 and repeats reception of data.

[0043] According to the sequence shown in FIG. 6, the user network 12-14 (FIG. 1) the data that has also been sent, arrives at the corresponding terminal device 2-4, and the waiting time until it is sent is It depends on the time from when the terminal devices 2 to 4 send a report until the data corresponding to the report is sent. In other words, it varies depending on the amount of data transmitted from all terminal devices 2-4.

[0044] For example, if all the transmission request amounts by reports from the terminal devices 2 to 4 are permitted, the waiting time until transmission of the output data of the report is greatly increased, which affects a service that requires real-time processing. This will have a significant effect on TCP (Transmission Control Protocol) throughput. Therefore, the station side device 1 needs to control the amount of data transmitted from the terminal devices 2 to 4 so that the waiting time in the noffer in the terminal device can be suppressed within an allowable time.

In the above sequence (FIG. 6), for example, when grant G42 is sent to terminal apparatus 4, the same grant G42 information is also sent from control signal processing section 104 in FIG. Based on this grant G42, the next received burst determination unit 106 transmits the transmission rate H (the next received burst (report R42 + data D41) during the gap between bursts before receiving the report R42 (report R42 + data D41). lOGbps) to the optical receiver 109 and the PON side receiver 107. Upon receiving the notification, the optical receiver 109 and the PON side receiver 107 make the reception function compatible with lOGbps and wait for the burst. Therefore, when the burst arrives, the reception system corresponding to the transmission rate H is ready, and synchronization can be established very quickly. Similarly, when the grant G32 is transmitted to the terminal device 3, the same grant G32 information is also transmitted from the control signal processing unit 104 to the next reception burst determination unit 106. Based on this grant G32, the next received burst judgment unit 106 transmits the transmission rate M of the next received burst (report R32 + data D31) during the interburst gap between data D41 and report R32. (2 Gbps) is notified to the optical receiver 109 and the PON side receiver 107. Upon receiving the notification, the optical receiver 109 and the PON side receiver 107 make the reception function compatible with 2 Gbps and wait for the corresponding burst. Therefore, when the burst arrives, the reception system corresponding to the transmission rate M is ready, and synchronization can be established very quickly. Similarly, since it becomes possible to quickly establish synchronization, the efficiency of uplink communication can be increased.

[0047] As described above, the station-side device 1 determines the next time to receive the uplink signal and the information on the transmission rate based on the grant given to the terminal devices 2 to 4 before actual reception. Obtainable. In addition, if a signal is received with the reception function corresponding to the transmission rate, synchronization can be quickly established. Therefore, it is possible to easily and quickly establish synchronization with the transmission rate of the upstream communication, thereby increasing the efficiency of the upstream communication.

[0048] Also, the main parts of the configuration necessary for this are a control signal processing unit 104 as a "management unit", a next reception burst determination unit 106, an optical reception unit 109 as a "reception unit", and the PON side The receiving unit 107. That is, the “management means” stores a plurality of types of uplink transmission rates used by the terminal devices 2 to 4 and gives the terminal devices 2 to 4 a grant of uplink communication, as well as the grant. Based on the above, it specifies the next time to receive the uplink signal and its transmission rate. In addition, the “reception unit” causes the reception function to correspond to the specified transmission rate in accordance with the timing. The functional procedures of these managing means and receiving means also constitute the upstream communication method of the PON system.

[0049] It should be noted that the management means may identify the type of the signal sign of the uplink signal in addition to the transmission rate, and the reception means may match the above timing. Thus, the reception function may be made to correspond to the specified code type. In this case, based on the grant given to the terminal device, it is possible to know the type of sign signal of the uplink signal to be received next before actual reception. In addition, if a signal is received with the reception function corresponding to the type of encoding, decoding can be performed quickly. Furthermore, encoded If the error correction code is an error correction code, it is possible to extend the distance that can be transmitted with the same transmission ratio with respect to the optical transmission power of the terminal device.

[0050] In addition to the transmission rate, the management unit may further specify the type of uplink signal encryption, and the reception unit may have a reception function in accordance with the time period. It may correspond to the specified type of encryption key. In this case, based on the grant given to the terminal device, it is possible to know the type of encryption signal of the uplink signal to be received next before actual reception. Also, if a signal is received with the reception function corresponding to the type of encryption, decryption can be performed quickly. Therefore, the confidentiality of communication with a specific terminal device can be improved.

[0051] In the above description, the terminal devices 2 to 4 are assumed to have already joined the PON system. Actually, however, the power is turned off from the power-off state that is not recognized by the station-side device 1. There is a procedure for the station side device 1 to recognize and join the PON system. This procedure is called the discovery process and is specified in Clause 64 of IEEE Standard 802.3ah—2004. Hereinafter, this disk process will be described.

In the first place, the terminal device before being recognized by the station side device 1 has no opportunity to be granted a grant. On the other hand, all terminal devices cannot perform uplink communication unless a grant is explicitly given from the station-side device 1. Therefore, the station side device 1 is turned on when the power is turned off (including unconnected), and is used to detect a terminal device (hereinafter referred to as an unregistered terminal device) to join the PON system. Run the process periodically and give the unregistered device a chance to respond.

[0053] FIG. 7 is a diagram showing a deskew process performed between the station side device and the unregistered terminal device. In the figure, the station side device starts the discovery process at time T1, and broadcasts a discovery gate message in the downstream direction. This discernible regist message includes information on the start time and length of the discernary period during which a response to this message is allowed. This discernable period is called a discernible rewindow and is, for example, a time ATd from time T2 to time T4.

[0054] The unregistered terminal device that has received the descanagate message waits for a random waiting time ATw having a random length from time T2 (synchronized with the station side device), and At time T3, a registration request message is transmitted to the station side device. This random waiting time ATw is a random value within a range in which the registration request message fits in the disk scanner window. Therefore, even if there are a plurality of unregistered terminal devices that intend to join the PON system, the probability that registration request messages from a plurality of unregistered terminal devices collide with each other can be reduced.

[0055] The registration request message includes the MAC address as the individual identification number of the unregistered terminal device. The station side device that has successfully received the registration request message assigns a logical link number (LLID) on the PON system to the unregistered terminal device, correlates the MAC address and LLID, and sign up. Next, the station side device transmits a registration message to the newly registered terminal device at time T5. The registration message includes the LLID of the terminal device and the synchronization time information necessary for the station side device to receive the upstream burst communication.

[0056] After that, at time T6, the station side device transmits a grant (grant gate message) that permits uplink communication to the terminal device. The unregistered terminal device that received the grant uses the grant to transmit a registered acknowledge to the station side device at time T7, which is received by the station side device, and the deskew process ends. After that, normal PON system communication starts.

[0057] In the configuration of the PON system shown in FIG. 1, for example, if the above discovery process is performed for all the terminal devices 2 to 4, the station side device 1 receives registration request messages from the terminal devices 2 to 4, respectively. I have to receive In normal PON communication after the terminal devices 2 to 4 have joined the PON system, as described above, the reception status of the station side device 1 can be adjusted based on the grant (the reception function corresponds to the transmission rate). Yes, but not at the unregistered stage. Therefore, the station side device 1 receives the uplink communication (registration request message) from the unregistered terminal device as follows, for example.

That is, even if the terminal apparatuses 2 to 4 have different transmission rates in normal PON communication, if one type of transmission rate (typically L) is used for the registration request message, Pre-reception power transmission rate is known.

Specifically, the terminal device 2 with the transmission rate L transmits the transmission rate L as in normal PON communication. Send a registration request message. On the other hand, when the terminal device 4 having the transmission rate H shown in FIG. 4 receives the discussion gate message, the terminal device 4 sends the message from the control signal processing unit 406 to the transmission unit switching determination unit 410. As a result, the transmission unit switching determination unit 410 switches the transmission function from the PON side transmission unit 405 to the registration request transmission unit 411. Then, the control signal processing unit 406 causes the registration request transmission unit 411 to transmit a registration request message at the transmission rate L.

Therefore, in normal PON communication, the terminal device 4 power registration request message of transmission rate H is transmitted at the transmission rate L. After transmitting the registration request message, the transmission unit switching determination unit 410 returns the transmission function from the registration request transmission unit 411 to the PON side transmission unit 400.

Similarly, in normal PON communication, the terminal device 3 having a transmission rate M transmits a registration request message or the like at a transmission rate L.

[0060] As a result, registration request messages received from the unregistered terminal devices 2 to 4 to the station side device 1 within the period of the discovery window (if two or three units are powered on at the same time, randomly Are all sent at the transmission rate L. On the other hand, the next reception burst determination unit 106 of the station side device 1 sends the transmission rate L of the next burst (registration request message) to the optical reception unit 109 and the PON side reception unit 107 in response to the discovery gate message. Notice. The optical receiver 109 and the PON side receiver 107 that have received the notification associate the reception function with the transmission rate L and wait for a registration request message.

Accordingly, the station side device 1 is ready to receive the transmission rate L when the registration request message arrives, and promptly and surely receives registration request messages from the unregistered terminal devices 2 to 4. Can be received.

As for the registered acknowledgement, the reception function of the station side device 1 is made to correspond to the transmission rate based on the grant given to the terminal devices 2 to 4 before the same as in the case of normal PON communication. Can do.

Claims

The scope of the claims

[1] A station-side device that configures a PON system together with a terminal device connected via an optical fiber and manages the terminal device,

Stores a plurality of types of uplink transmission rates used by the terminal device, gives an uplink communication grant to the terminal device, and receives an uplink signal next based on the grant. A station-side apparatus comprising: management means for specifying a timing and a transmission rate thereof; and receiving means for causing a reception function to correspond to the specified transmission rate in accordance with the timing.

[2] In addition to the transmission rate, the management means further specifies the type of uplink signal encoding, and the reception means specifies the reception function in accordance with the timing. The station-side device according to claim 1, wherein the station-side device is also adapted to the type of bag.

[3] In addition to the transmission rate, the management means further specifies the type of the encryption signal of the upstream signal, and the reception means specifies the reception function according to the time. 2. The station-side device according to claim 1, wherein the station-side device is also adapted to the type of key.

[4] An uplink communication method of a PON system in which a terminal device using a plurality of types of uplink transmission rates and a station-side device that manages the terminal device are connected via an optical fiber, the terminal device Stores a plurality of types of uplink transmission rates used by the mobile terminal, and grants a grant of uplink communication to the terminal device,

Based on the grant, specify when to receive the next uplink signal and its transmission rate,

The upstream communication method of the PON system, wherein the reception function is made to correspond to the specified transmission rate in accordance with the time.