Point2 Extends the Reach of 5G by 40 km in New Reference Design

As 5G continues to roll out, the industry is hastening to build the infrastructure necessary to support emerging technology. The challenges are technological as well as economic; networking companies aim to maintain high network performance while also demanding low-cost deployment and ownership.

In an attempt to address these needs, San Jose-based Point2 Technology has released a new reference design to extend the range of 5G up to 40 kilometers while also reducing the total cost of ownership for 5G network deployments.

 

Point2's RangeXtender. Image courtesy of Point2 Technology

 

In this article, we’ll discuss the purpose and function of electronic dispersion compensation and Point2's reference design as an example of this technology.

 

Fiber Optics in 5G and Dispersion 

While 5G is a wireless technology, its performance is still reliant on and limited by the performance of underlying wired communications. Specifically, 5G relies on optical fibers as the preferred medium for existing wireless backhaul networks. Here, optical fibers known as a fronthaul connect a dense mesh of 5G small cells. 

One of the most significant technical challenges facing the range and reliability of 5G networks is dispersion within these optical fibers.

 

Chromatic dispersion occurs when different light rays travel at different speeds. Image courtesy of FS

 

Dispersion in an optical fiber occurs when an input signal spreads out as it propagates down an optical fiber. This dispersion can be caused by several factors, including light rays traveling at different velocities, the interaction of light with electrons in the medium, and absorption of the light in some spectral regions. 

Dispersion is the distortion of the signal's features and the encoded bit symbols, ultimately making it harder to decode the input signal. Dispersion limits the range over which optical signals can be transmitted and the reliability with which they can be decoded.

 

What is Electronic Dispersion Compensation (EDC)?

To correct optical dispersion in fiber optic links, one popular technique is electronics dispersion compensation (EDC).

Eye diagram before and after EDC. Image courtesy of Synopsys

 

EDC is the process of using electronic filtering, also known as equalization, to compensate for dispersion within an optical link. Unlike other forms of dispersion compensation, EDC takes place in the electrical domain instead of the optical domain, leading to cost savings on a system level.

EDC is generally implemented through a transversal filter, where the output is the weighted sum of several time-delayed inputs. With this transversal filter, EDC corrects the inputted signal, allowing for more reliable decoding and extending signal range.

 

Point2's Reference Design Featuring "RangeXtender2"

In an attempt to improve 5G network performance while lowering the cost of ownership, Point2 Technology recently released a new 5G reference design.

 

Point2’s EDC technology. Image courtesy of Point2 Technology

 

The design, called the 5G RangeXtender2 is based on Point2’s new proprietary SoC. The SoC features several dedicated hardware blocks, including a PAM-4 modulation engine that converts electrical non-return-to-zero (NRZ) modulation to PAM-4 modulation, which offers a 50% reduction in data frequency.

With a decreased optical frequency, the network solution shows a greater immunity to the deleterious effects of optical dispersion, according to Point2. Along with the PAM-4 engine, the SoC features an EDC engine that combines bidirectional clock-and-data recovery and EDC together.  Again, this function is designed to reduce the effects of dispersion, helping to minimize bit-error rates and improve reliability.

Point2 says that 5G PAM-4 and NRZ module products that are based on the RangeXtender2 reference design may achieve ranges up to 40 km while also decreasing the total cost of ownership for 5G network connectivity deployments by 25%. Today, the reference design can support solutions up to 25 Gbps, but the company states that its product roadmap will deliver up to 100 Gbps in the future.