WDM-PON Network: An Efficient Solution for 5G Deployment

Driven by the rapid development of mobile communication industry, 5G network has boomed. However, 5G also faces some challenges such as the higher transmission bandwidth requirement. How to solve these problems? The WDM-PON network may be a better solution. This post will explain the advantages of WDM-PON technology and how it helps the 5G deployment.

Overview of WDM-PON Network & 5G

As it’s known to all, WDM-PON (Wavelength Division Multiplexing-Passive Optical Network) combines WDM technology with PON topology structure that allows operators to deliver high bandwidth to multiple endpoints over long distances. It includes some technologies, including colorless ONU technology, Auxiliary Management and Control Channel (AMCC), optical modules, OAM, and protection switching. With these key technologies, WDM-PON is regarded as an ideal solution which can meet the 5G requirements and has attracted great attention nowadays.

5G stands for the fifth generation of the wireless mobile network. It will be built on the foundation created by 4G LTE to allow people to send texts, make calls, and browse the web, etc. These upgraded 5G performance targets contain higher data rate, energy saving, higher-quality and massive device connectivity.

5G network

Why Choose WDM-PON for 5G Deployment?

As mentioned above, WDM-PON owns some useful technologies, which have unique advantages in 5G applications, including high bandwidth, low latency, low costs, fiber savings, easy maintenance, etc. The following will focus on introducing some of its merits.

High Bandwidth

The WDM-PON technology allows for traffic separation within the same physical fiber by different wavelengths. This results in a network that provides logical point-to-point connections over physical point-to-multipoint network topology. Moreover, AMCC signal modulation helps stack a management channel onto each wavelength. Therefore, the solution for carrying 5G front-haul over WDM-PON can offer a dedicated wavelength and extensive bandwidth resources to each user, saves time and increases transmission efficiency.

Low Latency

Having AMCC technology to deploy 5G, there is no need to use frame processing or dynamic bandwidth allocation (DBA) scheduling. This architecture provides low latency, low-frequency jitter, and flexible configuration of different front-haul interfaces.

Low Costs

With PON topology, it reduces the number of fiber needed by 5G front-haul networks with high site densities. The existing fiber infrastructure and equipment room are utilized, which saves the deployment and maintenance costs. What’s more, WDM-PON carries out an integrated front-haul/middle-haul (XHaul) transport network with the OLT. This OLT platform and the DU pool can be deployed in the same equipment room, which reduces the equipment construction costs. In addition, using the colorless technology of ONU in WDM-PON system results in low costs.

WDM-PON Network for 5G Deployment

Unlike the 4G which has the BBU and RRU two-level architectures, the 5G is constructed as three entities: CU (Centralized Unit), DU (Distribute Unit) and AAU (Active Antenna Unit). And 5G has three application scenario, including front-haul, middle-haul, and back-haul transmission. In the 5G Front-haul network, WDM-PON can be an efficient solution.

The following figure 1 shows the architecture of WDM-PON 5G front-haul network. Several RRUs and a DU are connected through a WDM-PON point-to-multipoint topology. The WDM-PON OLT is connected to the DU, CU, and ONU. ONU is also connected to RRUs. This OLT platform carries the front-haul traffic between the DU and RRUs as well as the middle-haul traffic between the DU and CU. In terms of the front-haul transmission or the connection between RRUs and DU, WDM-PON transmission interfaces play a significant role that enables the transparent user data transmission between them. In addition, the solution of applying WDM-PON to carry 5G is especially suitable for those operators who have to provide both wireless and wireline services in a greenfield scenario.

WDM-PON network

Summary

As boasting these advantages such as high capacity, low latency, cost-saving, etc., WDM-PON network is considered as an important solution for 5G. And the use of WDM-PON technology would become very common. To pave the way for the upcoming 5G network, HTFuture is striving to be the innovator in 5G communication. In fact, HTFuture has developed optical transceiver modules for WDM-PON network such as DWDM SFP+. If you have any needs, welcome to visit www.htfuture.com

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+, PON, Tunable, Copper, BIDI etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

EPON vs GPON Standard

EPON, based on Ethernet technology, is compliant with the IEEE 802.3ah (mid-2004) Ethernet in the First Mile standard that is now merged into the IEEE Standard 802.3–2005. It is a solution for the “first mile” optical access network. While GPON, or Gigabit PON, is expected to prevail as a leading optical access technology and to eliminate the bandwidth bottleneck in the last mile. Its requirements were set to force by the Full-Service Access Network (FASN) group, which was later adopted by ITU-T as the G.984.x standards.

EPON vs GPON Data Rate

In EPON, both downstream and upstream line rates are 1.25 Gbps, but due to the 8B/10B line encoding, the bit rate for data transmission is 1 Gbps. GPON, on the other hand, supports an asymmetrical data rate of 1.25 Gbps in both streams, as well as a data rate of 2.5 Gbps in downstream and a data rate of 1.25 Gbps in upstream. Hence GPON is better than EPON in this aspect. The following table has a brief comparison of GPON and EPON technology in the PON upstream and downstream bandwidth, bandwidth efficiency and the transmission.

EPON vs GPON Layering

Besides the above characteristics, perhaps the most striking distinction between the two protocols is a marked difference in the architectural approach, especially in layering. The image below will help you to figure it out.

In EPON, Ethernet frames are carried in their native format on the PON, which greatly simplifies the layering model and the associated management. EPON employs a single layer that uses IP (Internet Protocol) to carry data, voice, and video.

GPON, on the other hand, supports two layers of encapsulation. First, TDM (Time Division Multiplexing) and Ethernet frames are wrapped into GEM (GPON Encapsulation Mode) frames, which have a GFP-like format (derived from Generic Frame Procedure ITU G.7401). Secondly, ATM (Asynchronous Transfer Mode) and GEM frames are both encapsulated into GTC (GPON Transmission Convergence) frames that are finally transported over the PON.

The main purpose of the GEM frame is to provide a frame-oriented service, as an alternative to ATM, in order to efficiently accommodate Ethernet and TDM frames. With GEM, all traffic is mapped across the GPON network using a variant of SONET/SDH GFP. GEM supports a native transport of voice, video, and data without an added ATM or IP encapsulation layer. That’s why GPON supports downstream rates as high as 2.5 Gbps and upstream rates from 155 Mbps to 2.5 Gbps. It is much faster than EPON. However, EPON clearly offers a much simpler and more straightforward solution than GPON. The support of ATM and the double encapsulation of GPON serve no real benefit over a pure Ethernet transport scheme.

Cost Comparison

The use of EPON allows carriers to eliminate complex and expensive ATM and Sonet elements and to simplify their networks, thereby lowering costs to subscribers. Currently, EPON equipment costs are approximately 10 percent of the costs of GPON equipment, and EPON equipment is rapidly becoming cost competitive with VDSL.

Summary

It is hard to say GPON is better than EPON, or vice verse. They each have their merits and demerits. When it comes to certain IP/Ethernet services, EPON is more suitable and cost-effective. While GPON has its own advantages in higher bandwidth, faster transmission rate and supporting triple-play services. Until now, EPON is still the mainstream of PON, especially in the Asian countries, but GPON is expanding quickly lately.

If need more information, feel free contact Ivy from HTFuture: sales6@htfuture.com, HTFuture team are ready and happy to assist you.