Optical Transceivers Solution for 5G Fronthaul/Backhaul Bearer Network

With the commercially available of 5G technology, the development of 5G mobile and wireless networks has progressed at a rapid pace. The significant increase in base station density, along with demands on latency, bandwidth and network flexibility, have placed higher requirements on the 5G network architecture and associated transmission solutions. Thus elevating the quality of the pluggable optical transceiver modules applied in 5G networks. For 5G bearer network, FIBERSTAMP provides a complete optical transceiver solution, including industrial-grade 25G/100G transceivers for 5G fronthaul and carrier-grade 100G/200G transceivers for 5G backhaul.

5G Fronthaul Solution

FIBERSTAMP's 5G fronthaul transceivers are designed to support the eCPRI interface that is considered as an optimal choice for 5G fronthaul, to meet the strict requirements of bandwidth and latency (below 100µs). Considering the convenience and efficiency of network construction, the initial 5G fronthaul connection is based on fiber direct connection, which is supplemented by passive WDM connection and active WDM/OTN/SPN connection. Among them, fiber direct connection is easy to maintain but will consume more fiber resources. As a supplementary solution, WDM connection can save fiber resources and support a longer transmission distance than fiber direct connection. Luckily, FIBERSTAMP's 5G fronthaul transceivers support all the connections mentioned above.

Fiber Direct Connection

The fiber direct connection is used to link each AAU and DU, which can be deployed easily. FIBERSTAMP's industrial-grade 25G grey light optical transceivers, including SR, CSR, LR, ER Lite and BiDi options, will be the dominance of the direct connection in 5G fronthaul transmission. These optical transceivers support dual-fiber transmission up to 40km and single-fiber bidirectional transmission up to 10km.

Passive WDM Connection

Passive WDM connection can multiplex several wavelengths and transmit them on a pair of optical fibers or a single fiber to connect multiple AAUs to DUs to save the optical fiber resource. FIBERSTAMP's industrial-grade 25G colored light optical transceivers, including CWDM and DWDM options, support this connection up to 10km over dual single-mode fibers.

Active WDM/OTN/SPN connection

Active WDM/OTN/SPN connection needs to deploy OTN devices (such as WDM Mux/Demux, OADM, EDFA, OEO, etc.) between the AAU site and DU equipment room. It also utilizes WDM technology and provides multiple AAU-to-DU connections by using a pair of optical fibers or a single fiber. FIBERSTAMP's industrial-grade 25G grey light optical transceivers with a short transmission distance can be applied for connecting AAU/DU with WDM/OTN/SPN. And the connections between WDM/OTN/SPN network devices can be achieved by FIBERSTAMP's industrial-grade 25G/100G grey light optical transceivers. Compared with the passive WDM connection, the active WDM connection is more flexible, cost-effective, easily deployed, and is likely to be gradually used by the 5G operators.

Considering the budgets of the network, 10G optical transceivers might be applied for network deployment in the 5G fronthaul by some network service suppliers. Nevertheless, the industry prefers to use 25G optical transceivers due to that the network granularity is 25Gbps. That is to say, 25G and 100G may be the optimal choices for 5G fronthaul. For 5G fronthaul, FIBERSTAMP has launched a series of industrial-grade 25G/100G transceivers as shown in the table below.

Notes: The "IT" in the brackets means the Industrial operating Temperature range of -40℃ to +85℃ and the "ET" in the brackets means the Extended operating Temperature range of -20℃ to +85℃.

5G Backhaul Solution

FIBERSTAMP's 5G backhaul transceivers support both 5G midhaul and 5G backhaul. Since the requirements of bandwidth and networking flexibility are basically the same for 5G midhaul and 5G backhaul networks, they can utilize the same technology for transmission, like IPRAN (Internet Protocol Radio Access Network), PTN and OTN technology, etc. Two connecting methods for 5G backhaul network are presented below.

OTN & IPRAN Connection

The packet-enhanced OTN equipment with routing and forwarding functions are applied for the 5G midhaul transmission, while 5G backhaul network continues to adopt BGP protocol for routing and forwarding between IPRAN and OTN devices. In order to meet the demand for large capacity and network slicing of 5G, IPRAN will introduce high-speed interface technologies such as 25G, 50G, and 100G, or consider adopting new interface technologies such as FlexE (flexible Ethernet) to achieve physical isolation and offer better quality assurance for 5G transmission.

End-to-End OTN Connection

End-to-End packet-enhanced OTN network devices are applied for 5G midhaul/backhaul transmission. Compared with the above solution, it has strong networking capabilities and end-to-end maintenance capabilities to avoid the issues of interoperability and cross-professional coordination between OTN and IPRAN.

In addition, 5G midhaul/backhaul networks cover the access layer, aggregation layer, and core layer of the MAN (metropolitan area network), and the optical transceivers used in the core layer are similar to those used in existing transmission networks and data centers. Among them, the 25G/50G/100G grey light or colored light optical transceivers will be mainly applied for the metro access layer network, and the metro convergence and core layer network will mainly use 100G/200G/400G DWDM colored light optical transceivers. For 5G midhaul/backhaul, FIBERSTAMP has launched a series of carrier-grade 100G/200G transceivers as shown in the table below.

Currently, with the population of the 5G applications, there are multiple optical module technologies and solutions for the 5G bearer network, which poses huge potential and great challenges for the optical transceiver market. Since there is a large demand in the market for 5G optical transceivers, and the development of 5G optical transceivers is difficult at this moment, the prices might be a little expensive in the short term. It is believed that with the continuous maturity of 5G technology and applications, the price of 5G optical transceivers will gradually decrease in the future and the market is still promising.