KR101766792B1 - Hybrid optical network-on-chip system, and method of data transmission and reception in hybrid optical network-on-chip system - Google Patents

Abstract

The present invention relates to a hybrid optical network-on-chip system, and a data transmission and reception method therein. The hybrid optical network-on-chip system comprises: a plurality of routers receiving a multi-wavelength optical signal having multiple wavelengths and switching the wavelengths of the received optical signal; and a plurality of nodes connected to any one of the plurality of routers, transmitting data through a single wavelength optical signal, and receiving the data based on a multi-wavelength optical signal, wherein any one of the nodes included in the plurality of nodes transmits the data to another node included in the plurality of nodes through the optical signal generated based on a predetermined wavelength, and at least one of the plurality of nodes has a different predetermined wavelength.

Description

HYBRID OPTICAL NETWORK-ON-CHIP SYSTEM AND HYBRID OPTICAL NETWORK-ON-CHIP SYSTEM <br> <br> <br> Patents - stay tuned to the technology HYBRID OPTICAL NETWORK-ON-CHIP SYSTEM, AND METHOD OF DATA TRANSMISSION AND RECEPTION IN HYBRID OPTICAL NETWORK-

The present invention relates to a hybrid optical network-on-chip system and a method of transmitting and receiving data in a hybrid optical network-on-chip system.

Network-on-chip (NoC) has been developed to extend the performance of system-on-a-chip. That is, network-on-chip is an on-chip communication architecture.

Conventional network-on-chips utilize metal interconnects based on electrical interconnections and thus have physical limitations in terms of bandwidth, power consumption, and latency due to metallization.

In recent years, a silicon photonics-based optical network-on-chip (optical NoC) has been developed to solve the drawbacks of the conventional network-on-chip. However, there is a disadvantage that optical network-on-chips can cause crosstalk due to unwanted coupling between optical signals. Particularly, as the size of the on-chip network increases, the problem of noise due to crosstalk in the optical network-on-chip can become serious.

In this regard, Korean Patent Laid-Open Publication No. 10-2015-0026071 entitled "Device and Method for Designing a Hybrid Optical Network-on-Chip Topology" describes a method for designing a hybrid optical network- And a genetic algorithm detects at least one topology in which energy efficiency and response time are optimized among a plurality of topologies by applying a genetic algorithm technique, Discloses an apparatus and method for detecting an optimized topology through a fitness function based on loss cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hybrid optical network-on-chip system capable of receiving a single wavelength transmission multiwavelength capable of solving the problem of degradation of signal-to-noise ratio due to crosstalk and a hybrid optical network- A method for transmitting and receiving data in an on-chip system is provided.

It should be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

As a technical means for achieving the above technical object, a hybrid optical network-on-chip system according to the first aspect of the present invention comprises a plurality of routers for receiving optical signals of a plurality of wavelengths and switching wavelengths of the received optical signals and And a plurality of nodes connected to any one of the plurality of routers and transmitting the data through the optical signal of the single wavelength and receiving the data based on the optical signals of the multiple wavelengths. At this time, any one of the nodes included in the plurality of nodes transmits data to the other nodes included in the plurality of nodes through the optical signal generated based on the predetermined wavelength. And at least one of the plurality of nodes has a predetermined wavelength.

In addition, a method of transmitting and receiving data in a hybrid optical network-on-chip system according to a second aspect of the present invention includes the steps of: (a) transmitting, via an optical signal generated based on a predetermined wavelength, Transmitting data to another node included in a plurality of nodes; (b) a plurality of routers receiving optical signals, wherein a router connected to a corresponding one of the plurality of routers with an optical signal passes an optical signal to a node corresponding to the optical signal; And (c) receiving data based on the optical signal, wherein the node corresponding to the optical signal. At this time, as the predetermined wavelengths of the optical signals generated by the one or more nodes of the plurality of nodes are different, the plurality of routers receive the optical signals of the multiple wavelengths and switch the wavelength of the received optical signals, And transmits the data based on the optical signal of the single wavelength, and receives the data based on the optical signal of the multiple wavelengths.

The present invention allows each node to dynamically use the wavelength of an optical signal. Also, the present invention can minimize intra-crosstalk crosstalk considering the number of available wavelengths and maximize the signal-to-noise ratio in the worst case.

1 is an exemplary diagram of a hybrid optical network-on-chip system in accordance with an embodiment of the present invention.
2 is a block diagram of a hybrid optical network-on-chip system in accordance with an embodiment of the present invention.
3 is a pseudo code of a wavelength allocation algorithm according to an embodiment of the present invention.
4 is a flowchart of a data transmission / reception method in a hybrid optical network-on-chip system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when a part is referred to as "including " an element, it does not exclude other elements unless specifically stated otherwise.

The following describes a hybrid optical network-on-chip system 200 according to an embodiment of the present invention, with reference to FIGS.

1 is an illustration of a hybrid optical network-on-chip system 200 in accordance with an embodiment of the present invention. 2 is a block diagram of a hybrid optical network-on-chip system 200 in accordance with an embodiment of the present invention.

The hybrid optical network-on-chip system 200 according to an embodiment of the present invention may transmit data based on a hybrid optical network-on-chip. At this time, the hybrid optical network-on-chip system 200 may be a structure based on a single wavelength transmitter-multiple wavelength receiver.

The hybrid optical network-on-chip system 220 includes a plurality of nodes 210 and a plurality of routers 220. The hybrid optical network-on-chip system 200 may include an optical cable for connecting a plurality of routers 220 respectively or connecting the routers 220 and 210.

Specifically, the node 210 transmits and receives data based on an optical signal. At this time, the optical signal received by the node 210 may be an optical signal switched in the router 220 connected to the node 210. Also, the node 210 may be a core or a processor.

The node 210 can transmit data according to a predetermined wavelength. Therefore, the node 210 may include a laser source capable of generating an optical signal of a predetermined wavelength. For example, the laser source may be a vertical cavity surface emitting laser (VCSEL).

The plurality of nodes 210 have different predetermined wavelengths. However, some of the plurality of nodes 210 may have the same predetermined wavelength. For example, referring to FIG. 1, some of a plurality of nodes may have a predetermined wavelength equal to? ₀ . In addition, some of the predetermined wavelengths may be? ₁ ,? _2, or? ₃ .

And node 210 receives multiple wavelength optical signals. Therefore, the node 210 may include a photo detector (PD) and an optical filter capable of receiving an optical signal of a predetermined wavelength. The node 210 can receive optical signals of a predetermined wavelength that have passed through the optical detector and the optical filter among the optical signals switched by the router 220 connected thereto. The node 210 may receive the optical signal transmitted from the other node through the received optical signal of the predetermined wavelength.

In addition, the node 210 may include a modulator and a demodulator for modulating and demodulating the optical signal.

The node 210 may be a source node for transmitting data or a target node for receiving data.

Meanwhile, the routers 220 included in the hybrid optical network-on-chip system 200 are each connected to one node 210. Also, the router 220 is connected to one or more other routers.

At this time, the router 220 may be a network switch or a switching hub. For example, the router 220 may be a switch based on comb-switching technology.

Thus, the router 220 may receive an optical signal for data transmission from the node 210 to another node connected thereto. And the router 220 may transmit to the router 220 connected to the other node.

In addition, the router 220 can determine whether an optical signal received from another node is an optical signal transmitted to the node 210 connected to the router 220. If it is an optical signal to be delivered to a connected node, the router 220 may switch the optical signal and forward it to the connected node.

To this end, the router 220 may include a single micro-ring resonator (MR) capable of filtering optical signals. At this time, the micro-ring resonator can filter the optical signal into multiple wavelengths according to a predetermined wavelength interval. For example, the predetermined wavelength interval may be the spacing of the free spectral range (FSR).

On the other hand, the source node can transmit data to the destination node based on a predetermined wavelength. At this time, the destination node may be a node receiving data of the source node.

A possible optical path ( SC _i ) for the source node i can be expressed as: &quot; (1) &quot; Here, c _{i, j} is an optical path from the source node i to the destination node j . Also, C is all possible optical paths included in the hybrid optical network-on-chip system 200.

At this time, only one optical path can be activated at a time on the optical path SC _i . Therefore, in the hybrid optical network-on-chip system 200, intra node crosstalk is less likely to occur because each node 210 can transmit data through different wavelengths.

Intra-channel crosstalk is a concept that contrasts with inter-channel crosstalk. Inter-channel crosstalk is crosstalk that can occur in optical paths using different wavelengths, and intra-channel crosstalk is crosstalk that can occur in optical paths using the same wavelength.

As such, the plurality of nodes 210 of the hybrid optical network-on-chip system 200 can solve the intra-channel crosstalk problem if all of them use different wavelengths. However, the number of wavelengths that the node 210 can use in the hybrid optical network-on-chip system 200 may be limited due to manufacturing costs and technical problems.

Thus, the hybrid optical network-on-chip system 200 can allocate an optimized wavelength for each of the plurality of nodes 210 based on optimization techniques.

The wavelength allocation for the plurality of nodes 210 may be performed at the node 210 of the hybrid optical network-on-chip system 200. Or the wavelength allocation to the plurality of nodes 210 may be included in the hybrid optical network-on-chip system 200 or may be performed through a controller (not shown) connected thereto.

는 광학 경로 v의 신호에 대한 전력이며,

는 광학 경로 v에 영향을 미치는 광학 경로 _i 의 잡음에 대한 전력이다.Equation (2) represents the signal-to-noise ratio (SNR) in the optical path v . In this case, v is an optical path where crosstalk occurs and can be called a victim. Also, i is an optical path for generating crosstalk, which can be called an aggressor, and a _i can be the number of attackers. In Equation (2)

Is the power for the signal of the optical path v ,

Is the power for the noise of the optical path _i that affects the optical path v.

와 비례할 수 있다.At this time, the expression (2) can be expressed as the following expression (3). Therefore, referring to Equations (2) and (3), the signal-to-noise ratio of the optical path v is

. &Lt; / RTI &gt;

[Equation 4] is a mathematical expression for calculating a crosstalk noise power coefficient for any two optical paths SC _i and SC _j .

In this case, l _{i, s} is the source node of SC _i , and l _{j, s} is the source node of SC _j . Also, P _i is the power for the signal incident on l _{i, s} , and P _j is the power for the signal incident on l _{j, s} . l _c is the crosstalk-induced point. K _c is the crosstalk coefficient at l _c and L ( l _i , l _j ) is the optical signal power loss of the optical signal from l _i to l _j .

The hybrid optical network-on-chip system 200 can calculate all the intra-crosstalk interference costs that can occur in the optical path SC _i as shown in Equation (5), using Equation (4).

The hybrid optical network-on-chip system 200 minimizes the intra-channel crosstalk cost of Equation (5) to maximize the signal-to-noise ratio. In addition, the hybrid optical network-on-chip system 200 may repeatedly assign wavelengths to the optical path SC _j so that the magnitude of crosstalk by the optical path SC _j in the optical path SC _i decreases.

At this time, the hybrid optical network-on-chip system 200 may allocate wavelengths to the plurality of nodes 210 based on a minimum-maximum optimization (mini-max). That is, the hybrid optical network-on-chip system 200 can perform optimization to maximize the reduction in cost.

On the other hand, the number of attackers for each optical path can be changed. Also, a change in the number of attackers can affect the signal-to-noise ratio. Therefore, the hybrid optical network-on-chip system 200 can define the number of attackers ( a _i ) as shown in Equation (6).

The maximum number of hops in a maximum number of hops (hop) from the entire topology (topology) of the chip, the system (200), N ⁱ _{max _hop} optical path SC _i - [Equation 6] N _{max _hop} hybrid optical network in -one The number. Therefore, based on [Expression 5] and [Expression 6], the cost can be expressed as [Expression 7].

Hence, the hybrid optical network-on-chip system 200 can perform max-min optimization using Equation (7). The hybrid optical network-on-chip system 200 also computes the maximum-minimum optimization problem ( fmax ) for [Equation 7] using Equation 8 based on mixed integer linear programming (MILP) Can be expressed as:

를 만족한다.In this case, w _{j, k} is a binary variable indicating whether or not the wavelength k is allocated to SC _i . At this time, w _{j, k}

.

As such, the hybrid optical network-on-chip system 200 can perform optimization based on equation (8).

3 is a pseudo code of a wavelength allocation algorithm according to an embodiment of the present invention.

Referring to FIG. 3, the hybrid optical network-on-chip system 200 can perform optimization repeatedly, using meta-heuristic, for efficient optimization.

For example, the hybrid optical network-on-chip system 200 may set an initial value to any value. The hybrid optical network-on-chip system 200 can then perform iterative optimization based on two rules. At this time, the two rules are as follows.

First rule: Among the plurality of optical paths to which the wavelength p has been allocated in the previous step, the optical path with the largest cost increase is selected at the current step, and the priority for the selected optical path is increased.

Rule 2: Allocate a wavelength q different from the wavelength p for an optical path with a small increase in cost as compared to other paths among the optical paths selected by the first rule.

And the hybrid optical network-on-chip system 200 can allocate the maximum cost in the previous step to the optical path where the wavelength is not allocated.

The hybrid optical network-on-chip system 200 may repeat the optimization process according to a predetermined number of iterations. When the optimization is completed, the hybrid optical network-on-chip system 200 can transmit and receive data according to a predetermined wavelength for each node.

Next, with reference to FIG. 4, a method of transmitting and receiving data in the hybrid optical network-on-chip system 200 according to an embodiment of the present invention will be described.

4 is a flowchart of a method of transmitting and receiving data in a hybrid optical network-on-chip system 200 according to an embodiment of the present invention.

One node included in the plurality of nodes 210 of the hybrid optical network-on-chip system transmits data to another node included in the plurality of nodes 210 through an optical signal generated based on a predetermined wavelength (S400).

A plurality of routers 220 receive optical signals. A router connected to the node corresponding to the optical signal among the plurality of routers 220 transmits the optical signal to the node corresponding to the optical signal (S410).

The node corresponding to the optical signal receives data from the router connected thereto based on the optical signal (S420).

At this time, a plurality of routers receive optical signals of multiple wavelengths and switch wavelengths of the received optical signals. Further, the plurality of nodes are connected to any one of the plurality of routers, and transmit data based on the optical signal of a single wavelength, and receive data based on the optical signals of multiple wavelengths. And at least one of the plurality of nodes has a predetermined wavelength.

In addition, the router can switch the wavelength of the received optical signal based on one micro-ring.

In addition, the predetermined wavelength set at each node may be set based on the optimization technique.

Each node 210 included in the plurality of nodes 210 can transmit data based on a predetermined wavelength set based on the optimization technique.

The method of transmitting and receiving data in the hybrid optical network-on-chip system 200 and the hybrid optical network-on-chip system 200 according to an embodiment of the present invention is based on the assumption that each node 210 can control the wavelength of the optical signal flexibly Can be used. In addition, the data transmission / reception method in the hybrid optical network-on-chip system 200 and the hybrid optical network-on-chip system 200 can minimize intra-crosstalk crosstalk in consideration of the number of available wavelengths, The signal-to-noise ratio of the worst case can be maximized.

One embodiment of the present invention may also be embodied in the form of a recording medium including instructions executable by a computer, such as program modules, being executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

200: Hybrid optical network-on-chip system
210: node
220: Router

Claims (11)

In a hybrid optical network-on-chip system,
A plurality of routers for receiving optical signals of multiple wavelengths and switching wavelengths of the received optical signals and
A plurality of nodes connected to any one of the plurality of routers and transmitting data through an optical signal of a single wavelength and receiving data based on optical signals of multiple wavelengths,
Wherein one of the nodes included in the plurality of nodes transmits data to another node included in the plurality of nodes through an optical signal generated based on a predetermined wavelength,
Wherein at least one of said plurality of nodes is different in said predetermined wavelength,
Wherein one of the nodes receives an optical signal transmitted from another node through a router connected to the node,
Receiving data based on the received optical signal,
The plurality of nodes each comprising a laser source, a photodetector and an optical filter,
One of the nodes receives an optical signal transmitted from the other node through an optical signal of a predetermined single wavelength passed through the optical filter and the photodetector among optical signals switched by the router connected to the node, Optical network-on-chip system. delete delete The method according to claim 1,
The router receives and switches multi-wavelength optical signals through a comb-switch,
Wherein the comb-switch switches the wavelength of the received optical signal based on a single micro-ring resonator. The method according to claim 1,
And wherein the one of the nodes transmits the data according to the predetermined wavelength set based on the optimization technique. 6. The method of claim 5,
Wherein the optimization technique is based on a maximum-minimum optimization technique. The method according to claim 6,
The optimization technique is based on a max-min optimization technique and a meta-heuristic based on mixed integer linear programming,
Wherein the meta-heuristic repeatedly performs a maximum-minimum optimization technique based on the mixed integer linear programming, according to a predetermined rule. A method of transmitting and receiving data in a hybrid optical network-on-chip system,
(a) transmitting data from one node included in a plurality of nodes to another node included in the plurality of nodes through an optical signal generated based on a predetermined wavelength;
(b) a plurality of routers receiving the optical signal, wherein a router connected to a node corresponding to the optical signal among the plurality of routers transmits the optical signal to a node corresponding to the optical signal; And
(c) receiving data based on the optical signal, the node corresponding to the optical signal,
As the predetermined wavelengths of the optical signals generated by the one or more nodes of the plurality of nodes are different, the plurality of routers receive optical signals of multiple wavelengths and switch wavelengths of the received optical signals,
Each of the nodes being connected to any one of the plurality of routers, for transmitting data based on an optical signal of a single wavelength, receiving data based on an optical signal of multiple wavelengths,
The plurality of nodes each comprising a laser source, a photodetector and an optical filter,
Wherein one of the nodes receives the optical signal transmitted from the other node through an optical signal of a predetermined single wavelength passed through the optical filter and the photodetector among the optical signals switched by the router connected thereto, / RTI &gt; 9. The method of claim 8,
The router receives and switches multi-wavelength optical signals through a comb-switch,
Wherein the combo-switch switches the wavelength of the received optical signal based on one micro-ring resonator. 9. The method of claim 8,
Wherein the predetermined wavelength is set based on an optimization technique. A computer-readable recording medium recording a program for performing the method according to any one of claims 8 to 10 on a computer.

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