All About MU-MIMO

May 25, 2017 at 8:00 AM


Multi-user multiple-input multiple-output (MU-MIMO) is the next evolution of MIMO and is revolutionizing that way Wi-Fi routers operate. MU-MIMO allows routers to simultaneously send data to multiple devices. This is much more efficient than single-user multiple-input multiple-output (SU-MIMO) that many routers utilize. MU-MIMO allows all of your devices to simultaneously send and receive data from the router for multiple devices at the same time.


If you’re not excited about MU-MIMO yet, here are 5 reasons why you should be:


  1. 1.       MU-MIMO eliminates slow Wi-Fi speeds by making your router a super multi-tasker. Instead of sending little bits of information one at a time to each device, the router can now simultaneously transmit data to multiple wireless devices.


  1. 2.       MU-MIMO is great for video streaming and other high-bandwidth uses because it delivers a more dependable, faster Wi-Fi connection, there is a noticeable improvement in these data-demanding tasks.


  1. 3.       Not only do Wi-Fi networks get faster with MU-MIMO, they gain greater capacity. This means that home networks can service more Wi-Fi devices and public networks with many users will perform better.


  1. 4.       Even non-MIMO devices will experience improved performance. To fully utilize MU-MIMO’s benefits, devices must support the technology. But with MU-MIMO devices working faster, the router is free to communicate with other SU-MIMO devices.


  1. 5.       MU-MIMO costs less and is easier to implement than SU-MIMO. MU-MIMO doesn’t require multiple antennas or as much signal processing as SU-MIMO. It also uses a simpler standardized beamforming method that makes it easier for manufacturers to support.


As with everything, MU-MIMO does have some downfalls. For optimal performance, both the router and device must support MU-MIMO using 802.11ac on the 5GHz frequency. No more than four devices should be connected at one time, for full, optimal performance, and those devices should be stationary and not roaming. MU-MIMO also only improves the connection in one direction, from router to device, or the downlink, not the other way around. Still, MU-MIMO is slated to be a very impactful technology and potentially revolutionize the world of wireless networking. 


Fiber Connector Types and How They Work

May 18, 2017 at 8:00 AM


There is no shortage of options available when it comes to fiber optic cables. We’ve discussed the different fiber terms, what they mean and how to read them. Now, we’ll take a closer look at fiber connector types.


There are numerous fiber optic connectors on the market today. The most common connector types are LC, SC, and ST styles.


ST – This connector type is still widely deployed in fiber networks. These connectors employ a bayonet style mount and cylindrical 2.5 mm ferrule that’s usually made of ceramic, but sometimes is constructed of metal or plastic. ST connectors are spring-loaded, so they must be properly seated/aligned to avoid high-loss.


SC - These snap-in connectors feature a 2.5 mm ferrule that keeps them secure in the port. The snap-in design latches with a simple push-pull motion. These connectors are available in simplex and duplex configurations.


FC – These connectors also use a 2.5 mm ferrule. They screw-in to connect firmly, though the key must be properly aligned in the slot before tightening. FC connectors were the most popular connector type for many years, but have largely been replaced by SC and LC connectors.


MT-RJ – These duplex connectors house both fibers in one polymer ferrule. They use pins for alignment and are offered in male and female versions. This connector type is not very widely used.


LC – These connectors use a standard ceramic ferrule. What sets theses connectors apart from other styles is that they are small form factor connectors that use a 1.25 mm ferrule and are half the size of SC connectors. LC connectors have been the most widely used interfaces in networking equipment over the past 10/15 years due to their small size.


All of these connectors are available in both Single mode and Multimode versions. ST, SC and FC connectors use the same 2.5 mm ferrule size, so they can me mixed and matched when connected using hybrid mating adapters as shown here:






There are three optional polish types that can be applied to fiber connectors: physical contact (PC), ultra-physical contact (UPC) or angled physical contact (APC). Each polish type provides a different level of back reflection, which is a measurement, in decibels, of the light reflected off the end of a fiber connector, and can be critical in some applications.


Click here to watch our video on fiber optic connector types.


For an in depth look at fiber connector colors, check out this blog post.


White-Space Wi-Fi 802.11af

May 11, 2017 at 8:00 AM


Waste not, want not, seems to be a growing way of life for many people these days, and that theme will soon apply to the Wi-Fi spectrum as well. The IEEE standard 802.11af, also known as white-space Wi-Fi or White-Fi, will utilize the unused space in the TV spectrum, the TV white-space, to support Wi-Fi networks.


How is this possible?


Broadcast television coverage is organized to leave a certain amount of space between coverage areas to avoid interference. This results in a significant amount of space where channels are unused. 802.11af allows Wi-Fi applications that require less power to utilize the white-space between coverage areas without causing interference.


Why do we need White Space Wi-Fi?


The need for more spectrum is greater than ever. 802.11af fulfills this need by allowing wireless networks to take advantage of the white-space in the frequency spectrum. 802.11af provides support for operation in unused TV channels in the VHF and UHF bands, which adds white-space services to 802.11 WLAN devices and builds upon the 802.11ac offerings.


What are the benefits?


In addition to providing more spectrum for Wi-Fi use, 802.11af allows for long-range and low-power operation because it uses frequencies below 1 GHz. This means it will work more like a traditional Wi-Fi network to increase bandwidth over a long-range wireless local-area network (WLAN).


The lowest band used by current Wi-Fi systems is 2.4 GHz. 802.11af operates in the 6, 7 and 8 MHz channels, which makes it backward compatible with existing international TV band allocations.


Operation can be arranged for 1-4 channels, either contiguously or in two non-contiguous blocks, allowing devices to collect enough spectrum to achieve high data rates. Plus, there is a possibility that additional unused frequencies can be accessed to add even more capabilities.


Here is a chart showing the 802.11af frequencies and corresponding TV white-space channels:




White-space Wi-Fi 802.11af is not going to be the perfect solution for all applications. But it is going take processing technology to another level by providing access to more spectrum to meet today’s ever-growing Wi-Fi needs.


Up In Flames: Cable Flammability Ratings

May 4, 2017 at 8:00 AM


Fires can’t always be prevented, but with a plan in place, fires are more easily contained and people can be kept safer. The same principle applies when choosing cables for your communication network. Some cable materials can pose real threats when ignited, especially if the fire is in an enclosed space where evacuation is not an option. For this reason, cable flammability ratings were developed. Here, we’ll take a look at what these ratings mean and how to use them to keep yourself safe and keep your communications equipment from going up in flames.


Most commercially available cable assemblies have an outer jacket made from polyvinyl chloride (PVC). PVC is durable and flexible, making it a great option for many applications. But for all of its benefits, PVC has some serious shortcomings. In a fire, PVC cables can act as a flame accelerant and emit dangerous, toxic gases. Fortunately, there are cable jacket materials on the market that are less-flammable and much safer. These are especially good options for installations in enclosed spaces such as ships, aircraft, submarines, trains and other vehicles.


General Purpose (CM, CMG, CMx)

These cables comply with UL-1582. They will burn but they partially self-extinguish. These are often used for workstation cables and patch cords, but are not for use between building floors or in air plenum spaces.



Riser-rated (CMR)

Riser-rated cables are UL-1666 compliant and are designated for use in vertical tray applications such as cable runs between floors, through cable risers or in elevator shafts. In order for a cable to be Riser-rated, it must be able to self-extinguish.




Plenum-rated (CMP)

Plenum-rated cables comply with NFPA-262 and UL-910. They are the only cables permitted in spaces identified as air plenums, such as raised flooring systems and air handling ducts. Cables designated as plenum-rated are able to self-extinguish and will not re-ignite.



Low-Smoke Zero-Halogen (LSZH)


As the name states, these cables produce low-smoke and zero halogen, plus they are self-extinguishing. Because they significantly reduce the amount of smoke and eliminate harmful halogen from being emitted, they are used in enclosed spaces where smoke and fumes can injure people and equipment. For more information on LSZH cables and where they are used, check out this blog post.



 To see exactly how each of these cables burn, watch our cable flammability test videos.


Case Study – On-Ramp Wireless

April 27, 2017 at 8:00 AM


Imagine a wireless network with more reach, capacity and scalability than any other wireless network, including cellular. That network exists and it is called the On-Ramp Total Reach Network. On-Ramp created the first wireless network built from the ground up to power wide-area machine-to-machine communication. This network uses patented technology to achieve unprecedented reach, capacity and scalability.


On-Ramp’s innovative technology operates in unlicensed bands and utilizes weak signals, even if they are in high-noise environments or over long distances with immunity to high-interference. This process produces groundbreaking performance with drastically less infrastructure cost, making On-Ramp wireless an ideal solution for many applications including utility, energy, agriculture, tracking and other M2M applications.


The issue On-Ramp had was finding a partner that offered end-to end wireless networking products to meet all of their needs. They needed a complete wireless networking solution that was made to withstand the rigors of field use with minimal lead time while being competitively priced.


L-com was the perfect partner, able to meet the needs of On-Ramp’s Total Reach Network with a wide range of products that included coaxial adapters, surge protectors, 2.4 GHz Wi-Fi antennas and low-loss cable assemblies. With the help of L-com’s products, On-Ramp able to supply its customers with an innovative networking solution with unmatched performance, lower TCO and greater ROI.


To read the full details of this case study, click here.



© L-com, Inc. All Rights Reserved. L-com, Inc., 50 High Street, West Mill, Third Floor, Suite 30, North Andover, MA 01845