METHOD, SYSTEM AND APPARATUS FOR TRANSMITTING DATA

• US 20090226170A1
• Filed: 02/27/2009
• Published: 09/10/2009
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Zou, Shimin
• Granted Patent: US 8,315,520 B2
• Time in Patent Office: Days
• US Class Current: 398/79
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0064 Arbitration, scheduling or medium access control aspects
• CPC Class Codes: H04Q 2011/0088 Signalling aspects

Abstract

The present invention provides a method and a system for transmitting data. The OLT sets a multiframe indication and an upstream timeslot indication overhead in the downstream frame sent to the ONU. After receiving the downstream frame, the ONU determines the upstream bandwidth position according to the multiframe indication and the upstream timeslot indication overhead, and sends upstream data to the OLT from the upstream bandwidth position of the upstream frame. Through controlling the upstream data transmission by multiframes, each T-CONT carries an overhead area regardless of the length, and thus able to carry longer payload as against an equivalent overhead area in the prior art. In this way, the overhead area is saved and the bandwidth utilization is improved.

Claims

1. A method for transmitting data, comprising:

setting, by the Optical Line Terminal, OLT, a multiframe indication and an upstream timeslot indication overhead in the downstream frame sent to the Optical Network Unit, ONU;

determining the upstream bandwidth position, by the ONU, according to the multiframe indication and the upstream timeslot indication overhead after receiving the downstream frame; and

sending upstream data, through the ONU, to the OLT from the upstream bandwidth position of the upstream frame.

2. The method of claim 1, wherein the multiframe indication is a multiframe count bit, and the multiframe count bit is part of the bits in the superframe counter in the downstream physical-layer control block, or a multiframe counter bit that is set separately.

3. The method of claim 2, wherein if the multiframe count bit is part of the bits in the superframe counter in the downstream physical-layer control block, before the ONU receives the downstream frame, the method further comprises:

through the PLOAMd message, the OLT notifies the ONU to receive the downstream frame in the multiframe mode.

4. The method of claim 1, wherein:

the process, in which the OLT sets a multiframe indication and an upstream timeslot indication overhead in the downstream frame sent to the ONU, further comprises;

the OLT notifies the bit quantity required by the upstream bandwidth position to the ONU;

before the upstream bandwidth position is determined, the method further comprises;

the ONU retrieves the bit quantity from the upstream timeslot indication overhead located in the highest and lowest bits of the upstream bandwidth position respectively according to the bit quantity required for the upstream bandwidth position.

5. The method according to claim 3, wherein:

the process of setting the upstream timeslot indication overhead comprises;

setting the upstream timeslot indication overhead into different downstream frames according to the multiframe indication, the upstream timeslot indication overhead in different downstream frames is adapted to make up an upstream bandwidth position specific highest bits and lowest bits. The indication range of the upstream bandwidth position is greater than the maximum timeslot quantity of an upstream frame;

the process of determining the upstream bandwidth position according to the multiframe indication and the upstream timeslot indication overhead comprises;

according to the multiframe indication, retrieving the upstream timeslot indication overhead in different downstream frames to make up an upstream bandwidth position specific to highest bits and lowest bits.

6. The method of claim 5, wherein:

the upstream timeslot indication overhead in each downstream frame contains m bits, and the upstream bandwidth position retrieves m bits from each upstream timeslot indication overhead. If the upstream timeslot indication overhead that makes up the upstream bandwidth position is set to be located in L downstream frames, the range indicated by the upstream bandwidth position is 0 to 2^m*L;

further, if the upstream timeslot indication overhead that makes up the upstream bandwidth position is set to be located in L downstream frames and the upstream bandwidth position retrieves N bits in the upstream timeslot overhead, the range indicated by the upstream bandwidth position is 0 to 2^N,

in which m, L and N are positive integers.

7. The method of claim 1, wherein the determining, by the ONU, the upstream bandwidth position according to the multiframe indication and the upstream timeslot indication overhead after receiving the downstream frame, is specifically:

The ONU receives the upstream timeslot indication overhead in different downstream frames, and, according to the multiframe indication, determines how the bit of the upstream timeslot indication overhead in the downstream frame of the multiframe indication is located in the upstream bandwidth position, and then determines the upstream bandwidth position.

8. The method according to claim 3, wherein:

when the upstream bandwidth of the ONU is constant, the time length represented by the upstream bandwidth position is in proportion to the time length of the upstream frame;

or, when the upstream bandwidth efficiency of the ONU is constant, the physical-layer time overhead length for the ONU to handle upstream data is in proportion to the length of the upstream frame.

9. The method of claim 8, wherein the physical-layer time overhead is the enabling time overhead of the burst sending laser of the ONU, or the protection time overhead between upstream burst packets, or the preamble time overhead.

10. A system for transmitting data, comprising:

an OLT, adapted to make up a downstream frame structure, set a multiframe indication and an upstream timeslot indication overhead in the downstream frame, send the downstream frame to the ONU, and receive upstream data from the ONU; and

an ONU, adapted to receive downstream frames and determine the upstream bandwidth position according to the multiframe indication and the upstream timeslot indication overhead, and send upstream data to the OLT from the upstream bandwidth position of the upstream frame.

11. The system of claim 10, wherein the OLT is further adapted to allocate, according to the time length of the upstream frame, to the ONU an upstream bandwidth position for sending upstream data, and determine the upstream timeslot indication overhead included in each downstream frame in the downstream multiframe according to the upstream bandwidth position.

12. The system of claim 10, wherein the OLT comprises:

a transmission convergence unit, adapted to make up a downstream frame structure, set a multiframe indication and an upstream indication overhead in the downstream frame, and handle the upstream data from the ONU; and

an interface unit, which includes an upstream burst optical receiver and a downstream optical transmitter, is adapted to convert the frame signals from the transmission convergence unit into optical signals and send them to the ONU, receive the upstream data from the ONU and send them to the transmission convergence unit for processing.

13. The system of claim 12, wherein the transmission convergence unit is further adapted to allocate to the ONU an upstream bandwidth position for sending upstream data, according to the time length of the upstream frame, and determine the upstream timeslot indication overhead included in each downstream frame in the downstream multiframe according to the upstream bandwidth position.

14. The system of claim 12, wherein the ONU comprises:

a transmission convergence unit, adapted to retrieve the upstream timeslot indication overhead from different downstream frames and determine an upstream bandwidth position jointly specific to highest bits and lowest bits, generate an upstream burst frame according to the upstream bandwidth position, where the upstream burst frame includes an upstream overhead area and a payload area, set a physical-layer time overhead, which includes at least setting of a preamble time or a frame delimiting time, and send an upstream burst frame to the interface unit; and

an interface unit, which includes an optical transmitter for transmitting burst data and an optical receiver for receiving downstream optical signals, and is adapted to enable the laser before sending burst data according to the set laser enable time overhead, and disable the laser after finishing burst data sending.