5G is fast becoming a reality in many parts of the world. According to the Global Mobile Suppliers Association (GSA), 461 operators in 137 countries/territories are now investing in 5G, including trials, licenses acquisition, planning, deployment, and launches. Of those, 176 operators in 72 countries/territories had launched one or more 5G services.
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Through various innovations, wireless transport technology has consistently surpassed capacity demands through 2G, 3G and 4G transitions and remains on trajectory to continue in a 5G network. Reliability of wireless backhaul products has never been better, and costs continue to decline especially relative to fiber-based options. From a product point of view, many good and reliable options exist that cover all frequency bands and form factors to solve the problem of backhaul, small cell and other sub-applications.
In South Africa, as in many emerging markets, wireless backhaul has long been a proverbial bottleneck to network growth. Due to cost and logistics, fiber optic technology remains out of reach as a practical solution for most aggregation scenarios, save for urban applications where population density and shorter routes can justify the exorbitance.
Now with the advent of higher speed, higher throughput mobile phones and tablet PCs, higher-order networking technologies are being pressed into service. Standard microwave radio, while cost efficient and effective for crossing far-flung forests, monumental mountains and desiccated deserts with traditional payload such as voice calls and moderate data rate applications, was not designed for the connectivity and capacity requirements of Layer 3 services. Thus, the bottleneck has grown still narrower. Even to the point where standard microwave radio might be hitting its upper threshold for serving mobile broadband.
Technical marketing manager, Siphiwe Nelwamondo, recently sat down with Engineering News, to discuss these issues and the present and future of microwave radio backhaul in South Africa and across the continent. In addition, he delved into how microwave networking is bridging the radio-IP gap for Layer 3 services by running IP/MPLS protocols on converged microwave routers.
As more and more mobile services get pushed out to the edge of the access network, the imperative for Layer 3 will only grow. Even as 3.5G and 4G mobile users who depend on full-IP increase in number, a majority of second- and third-generation subscribers will continue to rely on circuit-based technology. Not to worry, Nelwamondo covers how TDM telephony will be supported in a converged microwave and IP environment.
The full article goes on to discuss how mobile operators will strategize providing enterprise services from the cellular base station with microwave networking, virtual routers and more.
Public safety agencies will soon experience a dramatic improvement in communications capabilities enabled by advances in technology. New broadband multimedia applications will give first responders and commanders alike far better situational awareness, thereby improving both the effectiveness and safety of all personnel charged with protecting the public.
The specific technology, now mandated by the U.S. Federal Communications Commission (FCC) for all new emergency communications networks, is Long Term Evolution, or LTE—a fourth-generation (4G) broadband solution. The FCC has also allocated licensed spectrum to ensure the best possible performance in these new networks. These FCC rulings support the goal of achieving an interoperable nationwide network for public safety agencies.
The FCC chose LTE based on its proven ability to support voice, video and data communications at remarkably high data rates that were previously only possible with wired links. Although there will be some differences in a nationwide public safety network involving capacity and coexistence with Land-Mobile Radio communications, lessons learned from LTE’s deployment in large-scale commercial mobile operator networks will help ensure agencies are able to achieve the FCC’s goal cost-effectively.
When people think of mobile security, they usually think of encryption for their smartphones, tablet computers such as the BlackBerry PlayBook or other wireless devices. Or they think of a remote “wipe” capability that can render any lost device blank of any data if some unauthorized party did in fact try to enter the device illegally. These wireless solutions are all state-of-the-art thinking in the mobile security community. And many wireless equipment OEMs and third-party mobile security providers offer them.
But they only protect the data on the devices. They only protect so-called “data at rest” once it’s been downloaded onto the iPhone or iPad. They don’t speak to the need to cover “data in motion” as it is transmitted over the air. Some parts of the over the air journey are protected by infrastructure in the form of Wi-Fi and GSM. One is notoriously subject to human failing to enable security and the other has been broken for sometime. And then there is wireless security for backhaul. In this area, there has not even been an industry standard or de facto standard established. And most microwave solutions providers don’t even offer options for wireless security on the backhaul.
Fortunately, this is not the case across the board. Strong Security on the Eclipse Packet Node microwave radio platform offers three-way protection for mobile backhaul security: secure management, payload encryption and integrated RADIUS capability. Read the embedded overview document in full-screen mode for more details:
If you are reading this post, then you probably have heard about “4G”, the 4th generation cellular network. For a cell phone user, 4G means improved data speeds that allow faster delivery of multimedia-based applications, see our previous post, What is 4G?, for more details. On the other hand, the network operator desires to spend a minimum on upgrading network infrastructure and prefers to buy a backhaul solution that supports current and near future capacity demands of a cellular network.
Thus, it is important to improve the capacity of wireless backhaul links. To increase transmission capacity, wider channel spacing can be used. However the wireless spectrum is expensive and may not be available in some countries. Using transmission in high frequency bands, such as 60 GHz and above, provides the bandwidth needed to increase capacity. However, very high radio frequencies increase the cost of radio components. In addition, 60 GHz links limit transmission range due to high absorption of radio waves by the atmosphere, making this solution somewhat cost inefficient. One efficient way of improving the capacity of a communication link is to increase the order of the digital communication modulation scheme used for transmission.
In simple terms, digital modulation is the process of mapping a group of data bits into an information symbol that gets transmitted, after up-conversion to the radio frequency (RF) of the link. The most popular digital modulation scheme used in wireless radios is known as quadrature amplitude modulation (QAM). For a given symbol rate, increasing the modulation order, or equivalently packing more bits per symbol, would be an effective way to increase the capacity of a microwave link. For example, each symbol in a 64-QAM signal represents 6 data bits, while for 256-QAM and 1024-QAM signals it represents 8 and 10 data bits, respectively. Therefore, 1024-QAM provides (theoretically) a 25 percent increase in capacity over 256-QAM and an impressive 67 percent increase in capacity compared to 64-QAM.
The price paid for achieving such an increase in capacity is more complex signal processing algorithms and stricter requirements for channel quality, e.g. higher signal-to-noise ratio (SNR) at the receiver is required. In that case, increasing the modulation order for some networks under normal operating conditions can have a diminishing return on throughput. This is due to the fact that the required SNR for an acceptable receiver performance rarely can be met.
Why this is the case? Let us briefly discuss the challenges in increasing the modulation order. Higher modulation order results in larger pool of symbols available for transmission. For example, for 64-QAM, there exists 64 symbols in a 2D grid (known as constellation points) compared to 1,024 symbols for 1024-QAM for the same grid size. Clearly, increasing the number of symbols (assuming fixed power) makes the symbols closer to each other in this 2D grid. Thus, data detection at the receiver becomes more susceptible to errors due to impairment.
In practical terms, receiver circuits are affected by thermal noise, clipping and non-linearity of power amplifiers, phase noise and many other distortions that are beyond the scope of this post. It is worth mentioning that increasing the signal power beyond some limits results in actually decreasing the received SNR since many of these distortions associated with RF circuits are dependent on the transmitted power. Rather, the way to increase the modulation order is to improve the detection schemes and build circuits that are less susceptible to power-related distortions, along with improving the correction mechanisms at the receiver for phase noise and other impairments.
At Aviat Networks, we have the expertise and knowledge to build the highest quality microwave radios that can work at cutting edge signaling schemes. We will make sure that our customers see a sizable return—not a diminishing one from increasing the modulation order. Our pledge is that microwave backhaul will always exceed the capacity requirements of our customers.
Ramy Abdallah,
Senior Signal Processing Engineer, Aviat Networks
Here at Aviat Networks we are focused on everything that is wireless transmission. With so much happening in the wireless industry, we wanted to join in the conversation and share our experiences and insights on the trends, technology, and business.
If you are reading this inaugural blog post it is likely we have a lot in common. While the main purpose of this blog is to talk about wireless transmission, we will also cover topics such as network evolution, software usability, services, and more.
Our initial blog posts will cover topics leading up to Mobile World Congress 2011. Over the course of the next three weeks, we will offer timely coverage and video excerpts from the show to keep you up-to-speed on the latest and greatest.
We encourage you to be part of the conversation since just hearing from us would be like having a conversation with ourselves. New viewpoints and constructive feedback are always welcome and we looking forward to hearing from you!
The Aviat Networks Team