The Future Viability of WiFi

Español: Logo WiFi Vectorizado

Español: Logo WiFi Vectorizado (Photo credit: Wikipedia)

Just last week I wrote a blog that talked about how busy the WiFi spectrum is getting. It seems like every telecom business is using or has plans to use the spectrum in a big way. Since I wrote that blog I noticed the following article which outlines how wireless companies intend to deploy WiFi transmitters as part of their urban cell sites (and any other cell site that experiences congestion).

Just about every telecom business has some use for WiFi. Telcos and cable companies are using WiFi in their data routers to spread their data around homes and businesses. The wireless carriers are all planning on using WiFi to offload their tremendously busy licensed spectrum. Businesses use it to set up public hotspots. Settop manufacturers are going to use it to serve multiple TVs in your home. Devices that connect to your TV like Roku and Playstation use it. And it is becoming the default spectrum to use for the Internet of things and billions of devices are going to be made WiFi capable.

So this raises the issue of whether there is some point when there is just too many different people trying to use the same spectrum in the same area at the same time. People use the WiFi spectrum because it’s free. But like any radio spectrum, it has physical limitations. At some point we can simply overwhelm a given spectrum band in a given area and it will not work well for any of the applications trying to use it. It sure seems to me like we are headed towards that possibility with WiFi. I am sure that everybody remembers in the 90’s when cordless phones came out. The spectrum got so busy in some neighborhoods that the phones just wouldn’t work.

Without getting too technical, let me discuss some of the issues associated with radio interference. There are a whole lot of different ways that interference can affect a spectrum in a given location. Consider some of the following:

Adjacent Channel Interference (ACI). The WiFi spectrum is not one big swath of data but is divided up into discrete channels. Earlier versions of WiFi used one channel per transmission, but the latest standards allow for bonding channels together. Many of the problems that are experienced in the real world with WiFi is that many of the devices using it are not built to the same high standards that you find in licensed spectrum gear. And so there are numerous devices that bleed usage into adjacent channels. When such a device is transmitting, it then not only uses the assigned channel but pollutes the two channels on both sides.

Electromagnetic Interference (EMI). This is the interference that we all remember when listening to AM radio. This is interference that comes from some outside source that can range from microwave ovens, computer terminals, solar flares, doorbell transformers, and hundreds of other sources. WiFi is not immune from external interference and so part of the spectrum is eaten through native interference.

Co-channel Interference (CCI). This is the interference that comes when more than one user us trying to use the same channel at the same time. In the voice world this is known as crosstalk, which we have all experienced on cell phones from time to time. But in a data transmission this manifests as slower data speeds since each concurrent user loses part of their signal.

Common Mode Interference (CMI). This is interference that comes from using spectrum to conduct two-way transmissions. This is basically interference between transmitting and receiving WiFi signals at the same time.

As we put more and discrete WiFi paths in the same neighborhood the effects of each one of these types of interference get magnified. In any given area there is at least a little bit of all of these types of interference. That is inherent in the way that radio waves interact with each other on a physics basis. There are engineering techniques that can be used to minimize interference. For example, it’s typical to put the transmit and receive signals as far apart as you can get them. But if you out enough different signals into the same environment there comes a point where no techniques can overcome the sheer facts of physical interference. The spectrum can get overwhelmed and essentially becomes worthless until the demand on it reduces.

I know there are a lot of scientists and engineers who look at all of the planned used for WiFi and just shudder. Because in urban environments it is likely that the spectrum is going to get overwhelmed and none of the uses will work as they should.

Do You Understand Your Chokepoints?

Almost every network has chokepoints. A chokepoint is some place in the network that restricts data flow and that degrades the performance of the network beyond the chokepoint. In today’s environment where everybody is trying to coax more speed out of their network these chokepoints are becoming more obvious. Let me look at the chokepoints throughout the network, starting at the customer premise.

Many don’t think of the premise as a chokepoint, but if you are trying to deliver a large amount of data, then the wiring and other infrastructure at the location will be a chokepoint. We are always hearing today about gigabit networks, but there are actually very few wiring schemes available that will deliver a gigabit of data for more than a very short distance. Even category 5 and 6 cabling is only good for short runs at that speed. There is no WiFi on the market today that can operate at a gigabit. And technologies like HPNA and MOCA are not fast enough to carry a gigabit.

But the premise wiring and customer electronics can create a choke point even at slower speeds. It is a very difficult challenge to bring speeds of 100 Mbps to large premises like schools and hospitals. One can deliver fast data to the premise, but once the data is put onto wires of any kind the performance decays with distance, and generally a lot faster than you would think. I look at the recent federal announced goal of bringing a gigabit to every school in the country and I wonder how they plan to move that gigabit around the school. The answer mostly is that with today’s wiring and electronics, they won’t. They will be able to deliver a decent percentage of the gigabit to classrooms, but the chokepoint of wiring is going to eat up a lot of the bandwidth.

The next chokepoint in a network for most technologies is neighborhood nodes. Cable TV HFC networks, fiber PON networks, cellular data networks and DSL networks all rely on creating neighborhood nodes of some kind, a node being the place where the network hands off the data signal to the last mile. And these nodes are often chokepoints in the network due to what is called oversubscription. In the ideal network there would be enough bandwidth delivered so that every customer could use all of the bandwidth they have been delivered simultaneously. But very few network operators want to build that network because of the cost, and so carriers oversell bandwidth to customers.

Oversubscription is the process of bringing the same bandwidth to multiple customers since we know statistically that only a few customers in a given node will be making heavy use of that data at the same time. Effectively a network owner can sell the same bandwidth to multiple customers knowing that the vast majority of the time it will be available to whoever wants to use it.

We are all familiar with the chokepoints that occur in oversubscribed networks. Cable modem networks have been infamous for years for bogging down each evening when everybody uses the network at the same time. And we are also aware of how cell phone and other networks get clogged and unavailable in times of emergencies. These are all due to the chokepoints caused by oversubscription at the node. Oversubscription is not a bad thing when done well, but many networks end up, through success, with more customers per node than they had originally designed for.

The next chokepoint in many networks is the backbone fiber electronics that delivers bandwidth to from the hub to the nodes. Data bandwidth has grown at a very rapid pace over the last decade and it is not unusual to find backbone data feeds where today’s data usage exceeds the original design parameters. Upgrading the electronics is often costly because in some network you have to replace the electronics to all nodes in order to fix the ones that are full.

Another chokepoint in the network can be hub electronics. It’s possible to have routers and data switches that are unable to smoothly handle all of the data flow and routing needs at the peak times.

Finally, there can be a chokepoint in the data pipe that leaves a network and connects to the Internet. It is not unusual to find Internet pipes that hit capacity at peak usage times of the day which then slows down data usage for everybody on the network.

I have seen networks that have almost all of these chokepoints and I’ve seen other networks that have almost no chokepoints. Keeping a network ahead of the constantly growing demand for data usage is not cheap. But network operators have to realize that customers recognize when they are getting shortchanged and they don’t like it. The customer who wants to download a movie at 8:00 PM doesn’t care why your network is going slow because they believe they have paid you for the right to get that movie when they want it.

Unified Communications

One of the most powerful feature sets available today is unified communications. Yet very few of my clients are selling it today. But if your customer base includes businesses or a lot of residential power users then you need to include unified communications in your product portfolio, and you need to sell it.

What is unified communications (UC)? UC is the integration of real-time communication services with non-real time services. Real time services include such things as voice telephony and VoIP, instant messaging, speech recognition, data sharing, collaboration and video conferencing. Non-real time communication services are often packaged under the name of unified messaging and include such features as voicemail, email, SMS and faxes.

There is no standard set of features that are included in a UC package and it seems that every company that offers it does it a little differently. So a carrier must typically build this product by tying together all of the components and features you already have available into a bundled product. Most carriers who own a softswitch and a voice mail server are capable of creating a basic unified communications product.

There are numerous value propositions that UC offers to end user customers:

  • Brings the ability to delivery any communications medium to any device, anywhere.
  • Extends the corporate network so that mobile customers can be productive from anywhere.
  • Gives the freedom to each individual UC user to tailor the product for the way they can best use it.
  • Can add telepresence technologies to let a UC user check the availability of other resources in his network. For instance a user can see if somebody is available to talk before they try to call them, eliminating the voicemail chain.
  • Can add collaboration and data sharing components which will make employees far more productive. Good collaboration software gives users the ability to share and work together on any document from any software platform simultaneously.

The value to a customer of UC is that it allows the customer to send a message on one medium and receive the same communication in another medium. This frees a customer from any restraints imposed by location or device and the perfect UC product will deliver any communications path to any device anywhere.

For example, a customer can receive an email on any device of his choice and also has the option to have the email content delivered as a standard email, or as a voicemail or text. Normally the customer can receive the medium, in this case an email, live in the medium for which it was intended, but can also opt to receive or store the email on a non-real time basis in any other medium.

The control for making the desired choices is given to the customer. To continue with this example, the customer can set up his UC to always receive emails in a certain format, for example, as a voice mail he listens to on his cellphone, or he can change his options on the fly during the day.

UC is a very powerful product for customers who grasp it and use it. It can make a customer sticky to your network if you give them the freedom to have complete control over their communications.

How do you create a UC product for your network? The first step is to decide what you want to offer. Not every UC system tries to deliver every communications product to every device. Many UC products instead are crafted to satisfy specific customer applications. If you own a softswitch you probably already own many of the components needed to build a simple UC product. For example, there are various features built into the feature packages on a Metaswitch that can be combined to create a decent UC product. And if you only have a few business customers who will be interested in UC, this might be sufficient.

The other alternative is to buy a UC product from somebody else’s platform. Today there are numerous companies who have assembled UC products that function on their own platforms. As a carrier you can access these platforms on a wholesale basis and buy ready-made UC products for your customers rather than build your own UC products from scratch.

There has been a lot of industry activity in developing UC products in recent years. Since March 2008 there have been several open source UC projects based on Asterisk that has led to the creation of open source UC product lines. In May 2010, the Unified Communications Interoperability Forum (UCIF) was created to develop standards between technology companies for UC and to create interoperability profiles, implementation guidelines, and best UC practices. The original founding members were HP, Juniper Networks, Logitech, Microsoft and Polycom.

Because UC can be done in many different ways and can include numerous product components you can save a lot of time before trying to create a UC product by talking to CCG.