Research on WDM-PON load 5G application scenarios and Technologies

WDM-PON Hosting 5G Scenarios

Pre-PASS network schema definition

With the rapid development of mobile internet and the emergence of a variety of new applications such as the Internet of Things, the fifth generation of mobile communications (5G) technology came into being in response to the future explosion of mobile data traffic and massive equipment connectivity. In 2015, ITU-R formally defined three typical application scenarios for 5G: EMBB, MMTC, and URLLC.

EMBB corresponds to 3d/Ultra HD video and other high-traffic mobile broadband services, MMTC corresponds to the large-scale IoT business, and URLLC corresponds to such as driverless, industrial automation and other need for low Singo reliable connection of the business. November 28, 2016, China Mobile released a white paper on C-ran requirements, architecture, and challenges towards 5G.

Figure 1  BBU Research architecture: from 4G single node to 5G CU/DU two-level architecture

The 5G BBU feature will be reconstructed into Cu and du two functional entities (see Figure 1), Cu mainly includes non-real-time wireless high-level protocol stack functions, while supporting part of the core network function sinking and edge application business deployment, du equipment mainly handles the physical layer function and real-time requirements of the Layer 2 function, the front pass is divided into two levels,

First-class prequel and level two prequel.

The presence of CU enables some of the functional centralizations of the original BBU, which is compatible with a fully centralized deployment and also supports distributed DU deployments. The two-level prequel C-ran architecture provides network support for Du pooling or CU pooling. One of the first levels of the prequel is Fronthaul, can support ECPRI and other pre-transmission protocols, the second level of the prequel is also known as Midhaul (Middle pass).

Fronthaul and Midhaul have different latency and bandwidth requirements for different 5G services. 5G Front Pass and return of the large bandwidth requirements, driving the transmission network of large interface requirements, mainly including high-speed Ethernet interface or OTN/DWDM and other transmission interfaces. At the same time, with the new prequel interface definition of ECPRI, the network architecture evolves into a new architecture supporting Du and CU pooling, which presents new opportunities and challenges for wireless access and 5G hosting.

WDM-PON Hosting 5G Scenarios

Figure 2  5G new scene or hotspot scene

When operators have base station location pressure or need to release the Bbu room or dense urban areas need to centrally deploy the Du pool, in which the DU position can be moved up and centrally deployed. Especially for operators with both wired and wireless services, the new scenario is ideal for the WDM-pon of front-pass interfaces. The OLT can take advantage of the access room, centralized deployment of DU, DU pool and Olt common site, for 5G URLLC business, it is recommended that CU also with the OLT, du Common station site. Du pooled co-stations will bring the user-side data transfer path closer to the collaboration requirements between DU, such as comp, and Du and CU common stations, which can make the midhaul disappear, and the 5G ran user face transmission delay is smaller.

Realization of Realization of WDM-PON technology and its significance of 5G carrying technology and its significance of 5G carrying

WDM-PON Architecture:

Figure 3  WDM-PON Architecture

WDM-PON key technologies are currently the main focus: colorless ONU technology, or ITU-T G. 989.2 and CCSA WR WDM-pon standard Explicit adjustable technology to achieve colorless ONU; the other is the Auxiliary Management Channel (AMCC) technology, namely RF Pilot-tone and baseband overmodulation. In WDM-PON scheme, the development of key technologies such as optical module technology, OAM Management, and protection switching plays an important role in the use of WDM-PON’s 5G bearing large planning. The relevant agreements are being discussed and developed in the standard organization.

Front-Pass hosting scheme

Fig. 4  WDM-PON Front transmission networking scheme based on OLT Unified optical Access Platform

WDM-PON OLT Equipment Unified optical Access platform for 5G mobile forward transmission at the same time, support wired optical access business.

5G du or Bbu pool and rru through the WDM-PON passive optical network connection, the realization of the mobile business prequel.

Wdm-pon as a 5G prequel program reflects the following technical features: 1.

Wdm-pon technology delay is small, can provide a separate network and the business performance guarantee for 5G, enterprise and business services; 2.

Large bandwidth, support per channel 10G and 25G rate, can meet the bandwidth requirements of the 25G ECPRI front transmission signal; 3. High transmission efficiency. Embodied in two aspects, one is exclusive bandwidth without DBA scheduling, logic Point-to-point.

The other is the management aspect, the use of AMCC signal tuning technology, management channel overlay at each wavelength, no omcc reservation, no Gemport resource reservation caused by waste.

Wdm-pon as a 5G prequel scheme will also embody value in engineering applications: 1. The WDM-PON programme is suitable for the coverage of densely populated urban neighborhoods.

Because of the “natural tree-shaped cable topology”, “Solid shift fusion business”, “dense coverage”. 2. You can share existing fiber base settings. 5G network deployment requires a large number of optical fiber resources, network architecture based on passive optical network point-to-multipoint tree network topology, can save a lot of fiber optic wiring resources.

At present, FTTx fiber network covers a wide range, line, and port resources are abundant, fully utilized, can reduce the cost of 5G network deployment, reduce duplication of investment, improve the utilization of current network resources, fast and perfect 5G network intensive coverage. 3.

Multiple wavelengths are converged by AWG and distributed to branch fiber transmissions, saving a large number of backbone fiber resources. 4. AWG has a smaller loss than power Splitter.

In the case of equivalent ODN networking, using AWG to replace more split means a farther transmission distance. 5. 5G and wired access can share room resources, such as local pop access points.

In particular, the machine room based on AO Reconstruction can play a comprehensive network, the advantages of flat investment. 6. Can share the OLT, to achieve access to home users, enterprise users and 5G base station in the same access.

Further, improve equipment utilization, save network equipment deployment costs, reduce computer room and other resource requirements. 7. After du pooling, it is helpful to realize the co-construction and sharing of wireless and wired access resources, and to build a future-oriented fixed-shift converged network. Including the integration of fixed-shift control surface, the realization of certification, billing and user information unification, etc., to achieve solid shift surface fusion UPF fixed-platform equipment, but also to achieve solid storage resource fusion, such as Cdn, mec resources.

2 WDM-PON standard progress and Operator’s appeal At present, the WDM-PON standard mainly studies the single wavelength 10G rate below (1.25G/2.5g/10g) of the WDM-PON system. When the single-wave rate is up to 10G, the mainstream technology of WDM-PON colorless ONU is adjustable technology. Standard organizations are beginning to focus on the application of WDM-PON in 5G, especially the WDM-PON system single-wave 25G rate. ITU-T G. Sup

The 5GP discussion group is advancing and discussing 25G WDM-PON. Since 2017, international operators have studied WDM-PON as a key program for the 5G prequel. French orange, the current network is mostly D-ran, C-ran not much, 5G C-ran, consider the CU in Ng-pop Point, 5G forward closely concerned and research WDM-PON. German-electric DT, considering C-ran, cu/du separation, CU concentrated in the convergence layer. WDM-PON is interested in the prequel. Aussie Telstra, for C-ran prequel, compares active DWDM and WDM-PON schemes. The country’s three major operators, China Telecom Research Institute actively promote WDM-PON testing and trial commercial; Chinese Unicom to 5G carrying the main push G. Metro, WDM-PON is technically similar and can be used as a simplified version of G. Metro, China Mobile to 5G carrying the main push flexed, WDM-PON can be integrated with it.

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