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How Load Balancing Makes Netflix and Chill Better

These days, it seems everyone is using more and more internet data so they can stream video. But if you’re like many RVers, you’re forced to access the internet much of the time using cellular connections that don’t have the high speeds you’re used to in the city. In rural America, where lots of RVers like to be, cell service speeds typically are in the ~5-15Mbps range. These speeds can be even less if you’re using a low-cost data plan that is “network managed,” which is “cellular speak” for: you are low in the queue with respect to network priority!

To combat this challenge, many RVers rely on multiple cellular connections with more than one carrier. But by themselves, those don’t resolve the problem. If you’re watching a Netflix video, it doesn’t matter that you have two or three cellular connections plus the RV park’s WiFi, unless you can use them all at the same time.

How Load Balancing Provides Multiple “Pipes”

In an earlier post, we provided an introduction as to how Load Balancing can enable you to use multiple cellular connections at the same time. With Load Balancing, it’s as if you have parallel “pipes” carrying data to your router. Even though the download speed of the data going through each of those pipes doesn’t change, the fact that there are more of them means that more data can flow to your router in each time interval. Think of the pipes as if there was water in them. If each pipe can provide 1 gal per minute, then, by having 5 of them, we can now get 5 gal per minute of water.

Visualization of Multiple Water / Data Pipes

So, let’s imagine that you have two internet connections, each providing 5Mbps of data (when they’re not being network managed). Even if you aren’t watching Netflix, you may have several people in the family surfing on laptops or iPads, or playing video games. Each person is capable of consuming several megabits per second in data. Don’t forget that Facebook and YouTube video are still video even if the screen size is small and the resolution is low.

It’s fairly easy to envision that having multiple internet “pipes” makes it easier for multiple people to engage in all these activities. It’s as if one pipe is providing data to mom, a second one to dad and, maybe a third to a teenage gamer.

A conceptual illustration of Load Balancing is shown in the following graphic which shows data calls going to all available internet connections in turn:

Example of Load Balancing Data Paths

The above concept of multiple data paths to multiple end users is fairly easy to understand. However, what’s a lot harder to understand is how Load Balancing helps when you want to watch Netflix. That’s because in our minds many of us envision a Netflix data stream as being just that, a continuous flow of data bits that come down the wire to us. It turns out that’s hardly at all how Netflix gets video to us.

How Netflix Delivers Content

The first thing you need to understand is that giant Content Delivery Networks (CDN) like Netflix are cloud-based, distributed systems that don’t exist in a particular location. So, when you click on a movie to watch, one of the first things the CDN determines is where you are located and what ground-based link is best suited for sending the data to you. If you’re enjoying yourself at the Grand Canyon, there’s no point to sending your movie through the internet from New York, for example.

Once the CDN decides where it’s going to send your movie from, it has to determine the speed of the data link you are using so it can send your video in a resolution your connection can handle. And it has to have available resolutions for both higher and lower speed links just in case your speed changes for better or for worse while you are watching.

Now, most of us have experienced the changes in resolution that Netflix (or other CDNs) can employ when your speed decreases. But what most of us don’t realize is that better CDNs, like Netflix, can even remove individual video frames in order to reduce the data flow! Resolution-reduction is sort of what happens when the reduced data rate can’t be accommodated by frame elimination and other tricks.

By now, some you are wondering how all of this helps explains how Load Balancing makes it easier to watch a Netflix video. Well, the answer to that is that once Netflix has decided how much data you need (based on the data rate your connection can handle), it doesn’t send it as a continuous stream. Rather, it sends it to you by the bucketful, and that’s where our water analogy comes into play.

How Buffering Comes Into Play

You may not realize that the CDNs provide you a buffer of 5-10 minutes of video before you start watching. That’s why there’s always a pause before your video begins, no matter how fast your connection is. Your buffer is filling!

Once your buffer is full and you start watching, all the CDN cares about is keeping the buffer level full. Contrary to how we might envision it working, the CDN keeps your “bucket full” using all the data it can get delivered to you. Every time your buffer gets low, it issues a call for more data. If you think of your buffer as a bathtub, then you can see that having extra pipes will enable it to fill faster. All that matters is that the level in the tub fills faster than the water goes down the drain. If the tub gets empty, the data stream stops and you get the dreaded re-buffering symbol.

In the following graphic, you can see the buffer filling and then repeated “data calls” to keep it filled. Furthermore, you can see that Netflix is relying on three TCP data streams to provide the data. Hmm, did I just say three data flows? Doesn’t that seem analogous to our multiple pipes?

Bandwidth Graph of Netflix Buffer

Although I admit that the above graphic was obtained from an outside source (Singh, 2018), the following one was taken directly from my WiFiRanger Aspen’s real-time data utilization display. For simplicity, I have only shown one data source, but the general nature of the graph is the same. Because my data streams were much slower than those used in the first example, the initial fill period took longer. However, after the initial fill period, the spikey nature of the refill data calls are very similar to those in the first illustration. Although it took some time for the initial fill period to complete, the video had started playback early in the process. There is no doubt that Netflix realizes people are impatient and wouldn’t want to wait for their video to begin.

Bandwidth Graph of WiFiRanger During Netflix Buffer

The key point to understand is that a video “stream” is NOT a steady stream of data in sequential order.

Clearly, the more “pipes” you can use to contribute to this refilling process, the better your video stream will be.

In summary, by allowing you to use multiple data pipes to fill your “bucket,” Load Balancing makes it easier to maintain high-quality data streams even with a bunch of relatively slow-speed connections.


References:

Netflix – How It (Actually) Works: Insights for Network Managers, by Harneet Singh, Apr 12, 2018

Load Balancing Techniques and Optimizations, by Jason Potter, Posted on April 2, 2019

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MIMO, SU-MIMO, MU-MIMO, finding NEMO? It’s all buzzword bingo to me!

There are times when even the most “techie” of consumers begins to wonder if there’s any way of making sense out of the barrage of features available in the rapidly evolving world of communications.  As soon as you think you understand something, it gets changed or placed.  Everything is a jumble of letters and numbers.   First there was CDMA, then 4G/LTE, now 5G.  And, of course there’s 802.11b/g/n and ac!   We’ve talked about these in previous blog posts. In this post I’m going to discuss a feature that goes by the acronym MIMO which stands for Multiple Input/Multiple Output.  You may have heard people saying that you “have to get MIMO antennas”; today we’ll talk a bit about what that means!

I’m sure that virtually everyone has, at one time or another, stared at the top of a cell phone tower and wondered why there were so many antennas clustered up there.  Why do they have to have so many antennas side by side?  We usually think about connecting to an antenna tower as if we drew a line from the top of the tower to our device.  But what if we could draw more than one line from a cellular tower to our device?  What if we could draw lines from our device to several of the antennas on the tower?  Could we get more data to flow between the tower and our device?

It’s easy to understand that if we were connecting water hoses from a water source to our RV we could get more water to flow if we connected several hoses in parallel.  Several hoses in parallel would act as if they formed a bigger pipe. 

It’s also easy to understand that if we were running electrical current through wires, we could safely pass more current through several wires than we could any single wire.

With digital radio signals the concept is similar, but the process is a lot more complicated.  If we had several antennas on the tower and several on our device, there’s no way to ensure that the signal from Antenna X on the tower gets to Antenna A on your device.  In fact, what Antenna A is actually going to see is a mixture of the signals from Antennas X, Y, Z, etc.  Likewise, Antenna B on our device is going to see a similar mixture of signals coming from each of the antennas that are broadcasting to you. 

Even if the exact same signal is transmitted by both antennas, what will be received by A and B is going to be a mix of all of that and that mix will also be supplemented by reflected signals which may even have slight time delays.  Quite often what’s done is to broadcast the same signal using two different polarizations as is shown in Fig 1.  Even though the both polarizations contain the same information, from a signal processing perspective we can consider them to be two different data streams and use digital signal processing to separate them.

[WARNING—MATH ALERT!  This next section uses a little bit of algebra; if you’ve given up math for retirement, you are free to skip to the next section!]

As a simple example, lets assume that the tower has two antennas broadcasting to you and we’ll call them  X and Y.  We’ll assume that your phone has two antennas and we’ll call them A and B.  Mathematically, the signal seen by antenna A on your phone can be represented as:

Signal A(t) = AxX(t) + AyY(t)  where Ax and Ay are the signal strengths of antennas X and Y as seen by antenna A all of which are functions of time (t)

Similarly, the signal seen by antenna B on your phone is going to look something like:

Signal B(t) = BxX(t)+ ByY(t)

For some of you these equations are going to bring back faint (painful?) memories from algebra because what we have in this example is nothing more than two equations with two unknowns.

Now the good news is that our little algebra course will end here—we’re not going to have to solve those equations ourselves.  But, thanks to modern signal processing techniques, our cellular modems do just that.  In fact, by solving these equations the two pairs of antennas on the tower and on your device can act as if they are two separate data transmission “pipes” so the amount of data you can receive in a given period of time is twice as much.

[This is the end of the MATH ALERT!]

A simple MIMO setup with twin antennas as we’ve described is called a 2×2 MIMO (2 transmit antennas and 2 receive antennas) and such simple systems are now common on smartphones, tablets, hotspots, etc.  In fact, 2×2 MIMO is now being superseded by 4×4 MIMO on some newer devices and nothing prevents systems from having even more than four.

If all of this wasn’t complicated enough, there’s actually a bit of difference between how MIMO operates in urban environments compared how it works in more rural ones.  In a rural environment multiple antennas on a cell tower essentially transmit the same signal but with coding differences (such as different polarizations) so they can be distinguished from each other.  A cell phone with multiple antennas can receive these transmissions and “compare” them.  By doing this the “accuracy” of the received signal is improved which results in an overall improvement in phone performance.  This most basic use of MIMO is called “transmit diversity and it can enable phones to achieve fairly high speeds with relatively weak signals. 

However, in a more urban environment, where there are more cell towers within range and more surfaces to cause reflections, different data streams can be transmitted from different antennas so that the data speeds achieved can be significantly higher that would be possiblle with a single data stream.  MIMO operating in this manner is said to be using “spatial diversity.”  For those of us who grew up in an analog broadcast world, an amazing aspect of spatial diversity MIMO is that it is actually beneficial to have reflections, the very things that used to cause “ghosts” on our old TV pictures. It’s the use of these reflected signals that enables MIMO to differentiate the signals coming from different antennas.  Figure 2 illustrates how urban reflections can be used in the MIMO process.  The red and purple signals travel on different paths and have different delays as a result.  Using signal processing both data streams are recovered and the total speed can be twice or more than the speed of either stream

So how does all affect how a phone performs?

Performance tests have demonstrated that going from 2×2 MIMO to 4×4 MIMO can give you improved wireless signal strength and speed.  For example, some tests compared the iPhone XR to the iPhone XS. The iPhone XR and iPhone XS have the same wireless modem, but the XR has 2×2 MIMO whereas the  XS has 4×4.  When both phones were both connected to a 4×4 MIMO LTE network, the 4×4 iPhone XS topped out at a download speed of just under 400 Mbps. The 2×2 MIMO iPhone XR topped out at right under 200 Mbps at the same signal strength.  That’s a pretty amazing performance improvement without any other differences between the two phones.  Figure 3 [reference 1] shows the insides of a Samsung Galaxy S8.  The cellular antennas are along the top and near the bottom.  It’s amazing how much is stuffed into these devices.

So, the next time you upgrade your phone, ask what type of MIMO it uses.

One additional consideration worth noting about MIMO is that using it reduces the benefit of having a simple cellular amplifier.  In fact, using an such an amplifier can actually result in a performance decrease because it will prevent the phone or hotspot from taking advantage of the speed increases that derive from MIMO.  When a MIMO-equipped cell phone is combined with a single-channel cellular amplifier all the embedded MIMO information is lost. Yes, the signal seen by the phone will be stronger, but all the advantages provided by MIMO will be lost.  Essentially, the phone will revert back to a 1×1 MIMO which is how we define a single antenna configuration.  The “rule of thumb” these days is that if you can obtain a usable data signal without an amplifier, you’ll probably be better off without it!  That’s not to say that an amplifier is never beneficial, but in many cases you may be better off just relying on MIMO to achieve maximum speed.

By now you should have basic understanding of how MIMO can improve your cell phone reception. Next month we’ll talk about how the same concepts can be applied to WiFi communications.

References:

IEEE Spectrum, “Building Smartphone Antennas That Play Nice Together”,  Sampson Hu and David Tanner, 10/23/2018

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4G. 5G, 5G+!!! Gee, why do I care?

Written by WiFiRanger Ambassador, Joel Weiss “docj”

To the average person, today’s cellular data marketplace is a jumble of technobabble. Carriers continuously boast of the capabilities of their networks while also claiming that even better service is soon to be available. At the same time several companies planning to establish satellite-based internet systems claim that users will be better off with those (when they exist)! If only there was a way to sift through the “Geek speak” to better understand what the situation actually is!

The acronym 4G LTE actually stands for 4th Generation Long Term Evolution and, believe it or not, it is even a registered trademark. It pertains to cellular transmission standards that were first proposed all the way back in 2004. To be called 4G LTE a cellular system has to be capable of providing at least 100 Mbps capability. 4G LTE is in use essentially all over the world and LTE phones can, with some specific exceptions, be used in most countries. 4G LTE replaced the 3G CDMA network used by some US carriers and that network will be shut down in the near future.

Even though people (and advertisers) use the terms 4G and LTE as if they are synonyms, in reality, the term LTE encompasses futures evolution beyond 4G.

So if LTE is what we have today, what comes next? I’ve heard people talk about Advanced LTE; is that the same as 5G?

Advanced 4G LTE is an improvement on “regular” 4G LTE but it doesn’t represent a whole new technology…For properly equipped cell towers and receivers (phones) Advanced 4G, sometimes called LTE+ in ads, can provide increased download speeds, up to ~300Mbps. To enable this, the cellular network essential permits a receiver to make multiple simultaneous connections to the network. It’s as if you phone or hotspot had two or more parallel connections to the same cellular tower. In “Geek speak” this is called carrier aggregation!

For carrier aggregation to work, the modem in your phone (the device that actually talks to the cellular network) has to be of an advanced type and it has to be communicating with a tower that has the proper hardware on it. Suffice it to say that at present, most of your phone and hotspots won’t yet support this capability and it is not uniformly available in the US.

To make matters even more confusing, some marketing flacks at AT&T decided to create a non-existent standard that they called “5Ge” which is nothing more than AT&T’s implementation of 4G LTE+. Irrespective of anything you hear in an ad, 5Ge is NOT 5G

So, if we don’t yet even have LTE+ why are we worrying about 5G? What would be different about 5G?

The 5G cellular system will be a completely new cellular implementation that will enable users to experience download speeds up to the Gbps range. Although, the actual speed obtained by users on any specific tower will probably be less than that, on the average most people will see download speed improvement of factors of at least 10 to 100. In addition, one of the advantages of 5G will be greatly reduced “ping times” (the time it takes for your “click” to reach the computer on the receiving end.) That would mean that a cellular connection would have plenty of bandwidth to support multiple video streams and/or to engage in real-time gaming

5G technology actually will come in three “flavors” and the implementation you encounter will depend significantly on which carrier you subscribe with and where you live. Different carriers have purchased the rights to use different sets of frequencies for their own 5G implementation. Furthermore, 5G implementation will be different in different parts of the country depending on the population density.

The following graphic depicts a portion of the electromagnetic spectrum and how our current and proposed communications networks fit together. The orange oval in the 0.8-2 GHz region is where today’s cellular phones and hotspots operate. The red oval shows the general spectral region called millimeter wave where the highest performance 5G systems will operate.

At the high performance end of the 5G spectrum there will be very high frequency 5G using what some people refer to as “millimeter waves.” The good news is that systems using mm waves will be capable of download speeds in the ~10 Gbps range. These transmissions will use frequencies of around 25 GHz. The bad news is that these wave are easily blocked by the walls of buildings, trees, rain and other obstacles and there will have to be many small “towers” to serve an area compared with the relatively small number of large towers we have today. Most people expect that this high frequency 5G will mostly be limited to urban and/or suburban environments.

At somewhat lower frequencies, in the 1-6 GHz range, there will be other implementations of 5G. Sprint had made investments in this frequency spectrum and other carriers are expected to use it also. Signals at these slightly lower frequencies will penetrate buildings and other obstacles better than do mm waves, but they won’t have quite as much penetration capability as we are used to with cellular signals today. The download speeds provided by 5G systems operating at these frequencies will be somewhat less than those made possible in the mm wave region.

At the lower end of the spectrum, there will be “low frequency” 5G and the carrier most aggressively pursuing this approach is T-Mobile which made a large investment in frequencies around 600 MHz, the so-called Band 71. T-Mobile is already using Band 71 for 4G LTE service, but later in 2020 it is expected to begin 5G operations using the same band . However, existing phones and hotspots that can receive Band 71 will not, in general, be able to receive 5G broadcasts on Band 71.

Furthermore, the physics of low frequency transmissions, however, limits 5G using these low frequencies to download speeds of ~100 Mbps. That might not compare with the Gbps speeds of higher frequency approaches, but it is sure a lot faster than the 1-10 Mbps speeds many of us live with today!

Wow, that’s a lot of information. When will all this happen?

5G is currently being rolled out by all the major carriers and is available in quite a few major metro areas. Here’s an interactive map of where you can already get 5G: https://www.digitaltrends.com/mobile/5g-availability-map/

It will probably take a number of years before the mix of technologies being offered by different carriers shakes out completely. Since I live in a relatively rural area, I doubt I’m going to see much of anything any time soon! But, no doubt our grandchildren will grow up in a word in which everything is wireless. “Grandpa, what’s that funny dish-like thing on the roof of your RV?”

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Two Connections Can Be Better Than One

Written by WiFiRanger Ambassador, Joel Weiss “docj”

Most of us who are dependent on cellular data connections know that even the best of them aren’t all that stable. In fact, if you use a speed test like speedofme.com you’ll observe that the speed of any cellular connection can vary rather dramatically even during the course of a speed test. In addition, both my OTR Mobile and my Verizon unlimited prepaid Jetpack SIM are subject to momentary “outages” lasting a couple of seconds. These often evidence themselves by brief rebuffering events on my YouTube TV.

Even though these brief outages are worse with plans that are heavily “network managed” even the hotspot on my postpaid Verizon plan exhibits significant variation on a moment-to-moment basis.

To combat this situation, I’m now using my WiFiRanger in Load Balance mode to “join” my two connections. The Ranger does not do true connection bonding (which is more complex and usually more expensive) but it does select which connection it wants to use for every webpage element or streaming segment. When one connection becomes slow the Ranger can choose the other. The result is that I’m now pretty much immune to the variabilities of my two connections. It’s not all that likely that both of my connections will slow at the same moment.

I’ve attached a screenshot which shows the real time data usage through my Ranger for a period of a couple of minutes. Usage through my Jetpack is shown in orange with the green representing the OTR Mobile AT&T hotspot. You can see how the load shifts from one connection to the other. You can even see moments when the green line seems to take over entirely from the orange one.

Screenshot of Control Panel with Load Balanced Ethernet WAN & Cellular Usage

What we’re doing here won’t help you if neither of your connections is fast enough to stream video, but it is quite helpful if you are concerned about moments during which one of your connections may drop below the threshold for high resolution streaming. When that happens, the router simply shifts the data stream to the other connection.

I won’t try to claim that WiFiRanger is the only router that has this Load Balance capability. But, typically, it is found in higher priced devices. If you’ve never tried it you might find it useful. It’s available on all WiFiRanger products including the new Converge models. It’s easy to set up and doesn’t limit your internet usage in any way.

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Making Your RV’s Internet Connection Nearly Unbreakable

Screenshot of the Realtime Bandwidth Utilization graph from the WiFiRanger Control Panel showing usage from multiple internet sources at the same time.

Written by WiFiRanger Ambassador, Joel Weiss “docj”

By now most RVers are pretty well acquainted with the difficulties inherent in trying to maintain 24/7 internet connections when your only options are cellular connections. There are many, many threads on the subject.  Even the best of cellular connections can result in varying download speeds on a continuous basis.  Quite often the download speed can vary from superb to downright awful over a very short time interval. 

Continue reading Making Your RV’s Internet Connection Nearly Unbreakable
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Bars? Decibels? I Just Wanna Make a Phone Call!

Photo of a smartphone with a speedtest of LTE data.

Written by WiFiRanger Ambassador, Joel Weiss “docj”

From time to time most RVers find themselves in situations where making a simple voice call is difficult and using the Internet is PAINFULLY slooooow or impossible. It’s true that many of these issues start and end with signal strength from our device to the cell tower; but, how do we know for sure that’s the problem?

Continue reading Bars? Decibels? I Just Wanna Make a Phone Call!
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What’s the Best WiFi + LTE for Your Specific Rig During Your Specific Travels

Photo of happy young man with his head of the vehicle window while traveling down the road.

Written by WiFiRanger Ambassador, Joel Weiss “docj”

Maintaining an internet connection is no longer a luxury for many RVers. Although conventional thought may be that the RV community is populated by retirees, there are an increasing number of working people who now live at least part time in their RVs. Add to that group the huge number of RV “vacationers” who travel with their families and who want to maintain connectivity for all their web-enabled devices. The bottom line is that millions of RVers want and need stable internet connections.

Continue reading What’s the Best WiFi + LTE for Your Specific Rig During Your Specific Travels
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Saving Money on Cellular Data Plans

Photo of elderly couple surfing the internet on a laptop while outside enjoying a picnic.

Nothing quite motivates like money, especially for those on a limited budget while traveling. As Cellular data costs continue to burden those with a mobile lifestyle, alternative internet sources are being sought out. Free WiFi has been ubiquitous and readily available to most travelers, but unfortunately the signal strength, security, and speeds have been lacking. Until an adequate solution is discovered, travelers find themselves stuck between the high cost of Cellular data or the poor performance of free WiFi.  

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Improving Range with Line of Sight (LoS)

Photo of young woman looking through binoculars to see what is far away.

Wireless transmission is most effective when there is clear, unobstructed line of sight between the receiver and transmitter. In the case of WiFi, all sorts of factors need to be considered in order to improve wireless range, such as avoiding obstacles, minimizing wireless interference, and having the best wireless equipment for maximum range. In this article, we will focus on perhaps the most critical component to maximizing wireless range with what you have— Line of Sight (LoS). 

Continue reading Improving Range with Line of Sight (LoS)