Packet Microwave: the future network
Featured Correspondent: Siân Harris for Layer123
With small cells and LTE making the headlines at Layer123’s first Packet Microwave conference, vendors were ready to show off a range of technologies to help make these networks happen.
As operators plan how to develop their mobile networks to handle the rapidly-growing levels of data traffic, the question of backhaul is a pressing consideration. Speakers and exhibitors at Layer123’s recent Packet Microwave conference in London highlighted the important role that Microwave plays in this, with a range of different options to suit different network configurations.
“There will be a new definition of high-capacity Microwave: greater than 155 Mbps. A few hubs will carry a lot of traffic,” said Andy Sutton, principal network architect at Everything Everywhere. “Options to help achieve this include dual polarizations with X-PIC, HOM schemes, AMC and wider RF channels.
”When it comes to small cells – metro, micro and pico cells that complement macro cells in areas of high traffic density – there are many more things to consider too.
Network topology is one evolving area. As Paolo Volpato, product strategy manager – wireless transmission of Alcatel-Lucent, stated at the Packet Microwave conference: “The tree is the most common topology today, and chains are also common. The evolution of small cells is leading to more complex structures and we are seeing more and more ring architectures being requested in real Microwave networks.”
And there are other things to take into account in designing small cells and the equipment to deploy in them. “Microcells are great things but what do they mean at street level?” asked Alan Solheim, VP of corporate development at DragonWave. “It is not just a technical issue now. At a street level, aesthetics matter.” He pointed out that in New York City only two types of box are permitted on the city’s streets, irrespective of whether the contents are the controls for traffic lights or part of a small cell for a mobile network. For this reason, distributed systems going up the sides of buildings or very large antennas, with corresponding high power requirements, are not feasible either.
There are also other new challenges in urban areas, as Leo Macciotta, senior marketing manager, network department for Huawei, noted: “Even if you mount a very small line of sight radio on a lamppost how is it affected by wind or traffic going by? And there are new challenges posed by ‘urban canyon’ propagation. Traffic is not really an issue but trees are.”
He noted that using non line of sight technologies can address the issues of trees but it also brings problems such as self-interference issues and limited capacity.
And there are other challenges for such cells such as the need to power the Microwave equipment and protect it from environmental damage. What’s more, said Macciotta, complex network topologies require families of products to be used, with simple products at the end of a chain but equipment that is capable of handling more capacity at hub sites.
The best Microwave technology solution for small cells is still up for debate too. “Small cells present new backhaul challenges, including location, power, cost point and synchronization,” said Andy Sutton of Everything Everywhere. “Radio systems can address the small cell backhaul challenge but many options exist.” These options include line of sight, non line of sight, point to point, point to multipoint, multipoint to multipoint, mesh, static or self organising (SON), low-band and integration into macro network or standalone backhaul.
“We expect a mix of many solutions. It is a very open research area,” observed Macciota of Huawei. “Most of the backhaul products today have been point to point links.”
One important area that is interesting but still needs development is MIMO. The problem, according to Macciota, is that it requires an optimum separation between two antennas to work best and this separation depends on frequency. “If it needs, for example, 6m separation between antennas that’s not a mobile solution,” he said. “We’re investigating other ways to do this.”
Making use of E-band, or extremely high frequency Microwave spectrum, was another topic at the meeting. Macciota noted that technology in this area could be a complement or supplement to fibre, perhaps as a tail link to the macrosite.
And there is potential for further developments. Renato Lombardi, VP, Microwave product line at Huawei Technologies predicted in a panel discussion that new technology possibilities will open up as new semiconductors with lower power consumption – such as gallium nitride and silicon germanium – become available for microwave applications.
So what packet radios are available today? The exhibition at Packet Microwave Forum showed that there are many strong options for operators to choose from.
At the event, NEC showed three packet radios from the iPASOLINK family. The iPASOLINK radios are said to provide smart solutions for advanced mobile back haul network for 3G, WiMAX or LTE networks. iPASOLINK radios include both traditional TDM radio functions and advanced IP network functions. Features include: ultra high capacity transmission with adaptive modulation and XPIC technology in compact size IDU; high system gain with advanced error collection and new amplifier technology; high level packet networking functionality with IP and PWE; advanced multi-service QoS and VPN functions; Ethernet OAM for fault management and performance monitor; and multiple clock synchronization source.
Alcatel-Lucent says that its 9500 Microwave Packet Radio (MPR) helps networks transition from TDM to IP in their backhaul, while still supporting legacy TDM. It promises improved packet aggregation, increased bandwidth, enhanced Ethernet connectivity and the Quality of Service that end users require.
Features include: service-driven adaptive packet modulation; E1 in packet by pseudowire/circuit emulation services (CES); ATM pseudowire; service awareness; synchronization distribution; single packet matrix with high switching capacity above 16 Gb/s; radio capacity up to 4 Gb/s per radio channel; multiservice packet ring; XPIC configurations; LAG support; and SDH transport.
According to the company, the 9500 MPR is the first microwave platform in the market with pure packet transmission and no wasted bandwidth. And, when compared to TDM radios, the 9500 MPR uses 50% less space and 55% less power.
Steve Goddard, sales director of Ceragon Networks, which was one of the Packet Microwave exhibitors, said: “It used to be about voice; now it’s about data. That’s the bottleneck. It’s also about the bandwidth. We supply point to point solutions in the range 4GHz to 38GHz.
We can offer a ring conformation too.” For Goddard, quality is a very important consideration. “Equipment needs to be very reliable and endure ll weather conditions,” he said. “Backhaul is key to operators.”
The FibeAir family of products from Ceragon is intended to smooth the migration towards all-IP and carrier Ethernet networks. The products promise enhanced spectrum utilization, comprehensive synchronization solutions and powerful low-delay traffic management.
The FibeAir IP-10C is described as a perfect fit for network sites requiring zero footprint and cost-effective backhaul that is rapidly deployable. “The ruggedized single-box system withstands harsh weather conditions and can be easily mounted on towers, rooftops, lamp posts, traffic light poles and small outdoor mobile cell-sites,” according to the company. The product offers up to 1Gbps per carrier and promises quick, simple and reliable set up and energy efficiency.
The FibeAir IP-10 E- Series is an all-packet wireless backhaul solution that offer capacities of up to 2 Gbps per channel. It promises integrated radio and networking functionality, flexible synchronization and low latency.
Huawei Technologies was another key exhibitor at Packet Microwave. Its OptiX RTN 600 series is a digital microwave transmission system for data packets. The system is said to provide end-to-end transmission from the access layer to the backbone layer. It is available in two models, the OptiX RTN 620 and the OptiX RTN 605.
The company also offers the RTN900 series, a unified platform for TDM/hybrid/packet that supports both Synchronous Ethernet and IEEE1588v2. Thanks to the XPIC and header compression technologies, the maximized capacity of one channel can reach over 2Gbit/s, providing large bandwidth for mobile backhaul. Its zero footprint deployment makes the RTN 900 platform ideal for LTE micro sites, according to the company.
Another exhibitor, DragonWave, describes itself as a leading provider of high-capacity packet microwave solutions that drive next-generation IP networks, especially in wireless network backhaul. The company says that its Horizon solutions are renowned for their leading capacity, reliability, and spectral efficiency.
Offering 2 to 4 Gbps per link, Horizon Quantum occupies only half a rack unit and claims to consume the lowest power per bit of any solution today. It can be deployed with licensed and unlicensed spectrum from 6 to 38 GHz. It also provides up to 2.5x spectral efficiency improvement and 7 to 56 MHz channel size options. In addition, XPIC enables channel reuse.
DragonWave also offers the Horizon Compact backhaul network solution. This provides 800 Mbps full duplex capacity, 100ms adaptive modulation, 100ms ring/mesh switching and a "zero-footprint", hardened out-door-unit.
The Horizon Compact+ is a zero footprint solution that can eliminate rack congestion and minimize collocation space, two issues that were raised as challenges for operators at the Packet Microwave conference.
The fourth member of the Horizon family is the Horizon Harmony, a split-mount system that is said to achieve significant efficiencies by converging TDM, ATM, Frame Relay, IP and Ethernet traffic onto a single packet-based transport layer and a single management plane. It provides 1 to 2 Gbps capacity with DragonWave’s Bandwidth Accelerator and supports frequencies between 6 and 60 GHz.
Cambridge Broadband Networks was also an exhibitor at the meeting. “The key issue is delivering more for less. We offer point to multipoint solutions. The benefit is half as many radios and half as many antenna sites,” said Lance Hiley, VP Marketing at CBNL. This, he said, is an important consideration because the cost of deploying antennas is high. According to the company, its VectaStar microwave backhaul, which is available in two versions, typically saves operators 50%