I think that we often overlook one of the most important steps in deployment. The optimization process. This team finds more problems in the network than you may realize. Their goal is to make it a better operating network. They find all the deployment problems that happened. They find mistakes in the original design and installation mistakes. That’s right installers! They find mistakes and problems that force physical changes!
I would like to cover these heroes because they are the ones that take the system from performing “OK” to ranking high in the Root Metrics ratings. These are the groups that make the difference between the dropped calls and the seamless coverage. They are the ones that allow you to download that ever important Facebook page without missing a cat video! Let’s look at what these teams do.
Who is on the team? The optimization team is usually made up of:
• A project manager (PM)
• RF Engineer (RFE)
• Drive Team (DT)
These are usually the three components of the optimization. What they do is gather the data to test the performance of the system and make changes to improve performance and coverage. Sound easy? Let’s look at what is involved.
The PM is there to manage the teams, create reports, and guide each team to work together. You don’t want one person going off and wasting time and money. Someone needs to arrange the teams to work together and to organize the reports and to shuffle the paperwork from the drive team to the RF engineers and then prepare the report for the customer in such a way that they can understand it and probably in a format that they requested. The PM also needs to know what areas are to be driven at any particular time and the specific time of day they should be driven. If you are testing loading at rush hour you could impact live customers. This is not a good thing. Your customers come first. Loading at peak times may cause a bad quality of experience for paying customers.
The RF engineers are the ones who analyze the data, make adjustments and make recommendations. This goes deeper than the coverage. They also have to look at the loading, the bits per second, and the overall bandwidth. With the demands of the customer and the flexibility of LTE, this could span across several bands. LTE carrier aggregation can make the user’s device see multiple spectrums at the same time. The customer gets more throughput if the aggregation can make the multiple spectrums all pass the data looking like one big fat and happy stream.
This takes planning and engineering up front and testing to make sure it works. Also, you don’t want to interfere with your own system, no-harm testing may also be examined. So this is where the engineer has to look at more than just one site, they need to be aware of what the surrounding sites are doing. Interference can cause so may problems, and you have control of all of it. It takes careful planning and optimizations.
The drive teams are the ones who drive and walk around to collect the live data. Yes, they may be walking, but “walk teams” just doesn’t seem as appealing as drive teams. They use laptops, software, and usually a type of smartphone connected to the laptop. They track their coverage with a GPS for location, and the other devices will capture the data like signal strength, voice quality and handoff, download and upload speeds and handoffs, QoS of the connection, bits per second, and throughput, and the ability to connect and make a call and make data connections. Even though we look at data now, we still don’t want to drop any voice calls if possible. We need to keep the customer experience as pure as possible.
If you take all of this data, it is still not enough. There is also something called PCMD, per call measurement data that is used to analyze the coverage. The RF Engineering teams have to take all of this data and make corrections to the network. What corrections? Let me tell you!
I know that most of you think that it’s a simple change in the eNodeB or the maybe a router. It is not always that easy. The optimization team will find so many problems with the network, more than most of you realize. I made a list below just to cover the surface.
Just a few problems caught in optimization:
• Router problems, bandwidth or routing issues
• Core issues, setting adjustments in the MME or one of the gateways
• eNodeB settings are wrong
• eNodeB wrong neighbor lists, self-interference issues
• Handoff issues, could be in the eNodeB or the core
• Radio head cabling is wrong
• PIM problems at a site that were missed
• Antenna elevation, (up and down), is wrong and needs to be corrected
• Antenna azimuth, (left or right), is wrong and needs to be changed
• Bad cables on the radio head
• Dirty fiber between the BBU and Radio head causing lost data
• Power settings in the radio head
• Power settings in the radio heads of surrounding sites
• Antenna elevation and azimuth in surrounding sites
• eNodeB settings that affect QoS
• OEM problems, could be the BTS, the antenna, cables, fiber, etc.
The optimization team’s goal is to have the network improve to become excellent in user experience. This takes time and a good plan of attack. They can’t just go around and drive the network. They have a plan to execute and concentrate on a problem area to start. Then they can work their way outward. This needs to be organized and tactical. Time of day matters because you don’t want to affect live customers in that sector or surrounding sectors. The individual eNodeBs, the cell sites, and the clusters need to be looked at as a system. When looking at the system you see how it all works together. The changes you make may affect more than the site you are optimizing.
Then, get down to that individual component that may be causing an issue, change it, and look at the system again. They will need to identify the problem with one piece of equipment but the goal is to have a high performing system. Making one change in an eNodeB could negatively affect a nearby cell causing new problems to arise. So this process is not an easy one. The RFE team needs to look at the whole before changing a piece. They need to review the original design and update it and make constant corrections to improve the user’s experience.
When there is a system-wide problem, they call in a Tiger Team, which is usually a team of two to four people, maybe climbers, that need to change a part or repair a problem that has been found at several sites. This could be an OEM problem or maybe an issue with the original design or even faulty cabling. It happens. A Tiger Team would come in and make similar changes on a mass scale, this is very expensive and time consuming. Once the Tiger Team gets up to speed, it can move rapidly and efficiently. It’s the initial learning curve that will take some time. It may need to change out an antenna or jumper or simply change the elevation on antennas. It may be a critical part of the process if site work is needed.
The optimization process will be changing with the addition of drones and smartphone apps. There have been optimizations done with drones in the Dubai International Stadium, Dubai Sports City. It was a great way to quickly and efficiently do a full optimization and do it again and again as changes are made. How cool is that? Don’t expect to see that too soon in the United States because the FAA is so far behind the drone curve. We are hoping that with smartphones the apps can start making real-time measurements. These are all very new but exciting.
OK, enough about that. I hope you learned how valuable this part of wireless deployment is to the carrier’s success.
Wade Sarver is a consultant, analyst, blogger and podcaster that advises and speaks on wireless deployment. Specifically LTE small cell and DAS deployments, helping customers define strategies and tactics for wireless deployments. He can be reached at www.wade4wireless.com or 717.916.2634.