We have encountered a number of incorrect opinions about how to add capacity to an E-RAN installation. It’s time to clarify the concerns, and set the record straight.
Adding capacity to an E-RAN installation is done by increasing the size of backhaul connecting it to the mobile core. Further, the contemporary Ethernet Network Termination Equipment “NTE” that are implemented by Tier One operators, adding capacity is performed by an OSS system by increasing the logical rate on a 1Gbps Ethernet physical port. There is no need to visit the building, add additional Radio Nodes and cabling, or install new cards in a chassis.
In the balance of this post, we review the E-RAN technical characteristics that support the approach of increasing backhaul to add capacity to an E-RAN.
- Each SpiderCloud Radio Node (SCRN-310) offers 2 cells (sectors) of capacity, and supports up to 128 active users.
- Up to 100 SCRN-310s can be connected to a Services Node. The Services Node supports over 10,000 subscribers.
- The number of Radio Nodes in a building is based on coverage. Each radio node covers 750-1000 sq. m. (7,500-10,000 sq. ft.).
- A single 20Mhz wide LTE carrier can deliver up to 150Mbps of downlink to a mobile device.
- The fronthaul network supporting the cloud of Radio Nodes associated with a Services Node is typically a 1Gb PoE+ link to an Ethernet VLAN with a 10Gbps backbone that interconnects the switches.
To make sense of this, typical commercial structures in the USA and Europe allocate anywhere from 15-25 sq. m. per person (150-250 sq. ft.) and, for purposes of this Fact Check, we’ll use a density of 10 sq. m. per person. This means that the maximum population supported by a single RN-310 with 750 sq. m. of coverage will be 75 people – of which only a small amount will be consuming capacity from their serving Radio Node at any moment in time.
Clearly, there is a huge amount of RF link capacity available to serve the mobile devices in this example. Note that each RN provides more capacity to a 1,000 sq. m. area than many DAS (or remote radio head systems) provide to a 10,000 sq. m. building. We shared, in this post, our view of spectrum re-use and how the E-RAN is analogous to the wired network revolution that was led by the emergence of 10Base-T and Ethernet switches.
In our experience, there is rarely a situation in which an operator has to add a Radio Node due to RF resource contention.
Now, let’s look at the backhaul that connects the Services Node to the mobile core. When an E-RAN system is viewed from end to end, the sizing of the backhaul is generally the bottleneck in any performance scenario. What limits the capacity of an E-RAN system is the backhaul that the operator delivers. If the operator delivers 100 Mbps of backhaul to an E-RAN with 20 RNs, it will operate at <5% of its capacity. If an operator wants to add capacity to an E-RAN, all they need to do is to increase the backhaul coming into the building.
Fact Check Recap:
Question: How do you add capacity to an E-RAN?
Answer: Increase the size of the backhaul as-needed. No truck rolls or on-site work required.
To our readers, if you have additional questions or areas of interest around implementation, please contact us. We’re happy to Fact Check what you may have been told.
– Art King, SpiderCloud Wireless, Director of Enterprise Services & Technologies