To solve the problem of poor indoor coverage, service providers and enterprise IT managers are increasingly relying on denser nodes of faster wireless technologies, leveraging the latest developments in small cells and next-generation Wi-Fi. However, the wired portion of these networks face bottlenecks as the required transport bandwidth dictated by the wireless exceeds the capacity that these cables were intended to support when they were originally specified more than a dozen years ago.
Indeed, both small cells and next-generation Wi-Fi require multiple gigabit-per-second transmission rates, yet more than 90% of the wired infrastructure worldwide consists of Category 5e or Category 6 cables, originally designed to support up to 1 Gbps of capacity. Upgrading the cables to Category 6A or fiber would allow the transport of 10 Gbps, but the prohibitive cost and disruption created by wholesale replacement and installation of new cables render this option undesirable.
Network administrators traditionally face three possible options when confronted with this bottleneck:
1. Leave the legacy infrastructure in place and aggregate traffic over more cables.
2. Upgrade to higher-speed copper cabling supporting 10 Gbps bandwidth.
3. Upgrade to fiber-optic connections.
The former presents scalability challenges. The latter two pose significant cost barriers and entail considerable disruption to the physical plant of any building or campus.
The prevailing attitude on legacy infrastructure prevents a large majority of enterprise plant managers from replacing these existing cables. New cable pulls represent significant cost and their replacement could create structural problems within the physical plant. First-hand experience tells me that limited capital resources make many IT and network administrators reluctant to replace their cabling. This attitude was pervasive in numerous exchanges with customers, partners, end users and manufacturers.
However, a fourth alternative now exists, and it involves extending the life of installed cabling infrastructure by supporting up to 5 Gbps transmission rates on existing Cat5e/6 cables through the use of novel signaling technology. The advent of such a solution in the mobile and enterprise environment has started a flurry of OEM design activity by companies all vying to deliver Wi-Fi access points, campus Ethernet switches, client PCs and NAS, and small cell units. It allows network equipment to keep up with the increased capacity demands on the wireless networks without replacing a single cable of the installed infrastructure.
Enabling multigigabit rates over legacy cables offers two distinct solutions for both small cells and Wi-Fi networks and offers the most scalable approach to improving indoor coverage.
Wave 2 of 802.11ac Wi-Fi access points aggregate a maximum bandwidth of up to 6.9 Gbps. After removing the overhead of the wireless protocols, the back-haul bandwidth requirement is around 5 Gbps. The technology pioneered for multigigabit Ethernet transmission over 100 meters of Cat5e/Cat6 cables serves as the foundation of the NBASE-T Alliance physical layer specification. Founded in 2014 by Aquantia, Cisco, Freescale and Xilinx, the NBASE-T Alliance is a consortium focused on the development and deployment of products that support 2.5 and 5 Gbps speeds at up to 100 meters of Cat5e/Cat6 cabling in enterprise networks. It currently counts 34 member companies, and is growing rapidly as a response to the increased interest in the industry for this technology.
Small cell technologies, such as cloud radio access networks, face key bottlenecks in the way antennas connect inside buildings to the rest of the network and it prevents potential indoor coverage benefits from being exploited. In-building C-RAN promises a more versatile and scalable approach to indoor coverage in enterprise buildings and large venues such as stadiums, airports, shopping centers and college campuses where massive numbers of wireless devices demand connectivity. C-RAN architectures rely on remote radio units sending the digitized RF spectrum to a centralized baseband unit for processing, utilizing common public radio interface signaling for transport over copper cabling. As cellular technologies continue to push wireless capacity, the need to provide multi-Gbps bandwidth over copper has emerged, pushing the limits of what’s possible with existing physical layer solutions.
To address the multi-Gbps requirement in these small cell networks, another technology has been developed to provide the unique capability of transporting digitized cellular data at multi-Gbps rates over 200 meters of copper cable. Starting with a novel physical layer integrated circuit, this technology is designed to shatter a critical connectivity bottleneck in small cell deployments and enable service providers to cost-effectively deploy next-generation indoor C-RAN technology to address growing capacity and service-level demands. Using this kind of technology enables service providers to reap the benefits for their next-generation C-RAN investment without having to rewire their enterprise campus network.
Finally, we’ve also seen cases where cellular base stations are combined with Wi-Fi access points in so-called heterogeneous network configurations, allowing service providers to offload some of the cellular data traffic to Wi-Fi and improve quality of service and network capacity. Here as well, the migration to 802.11ac Wave 2 technology on the Wi-Fi AP side creates the need to upgrade the wired infrastructure to the multigigabit solution.
In summary, regardless of whether the topology relies on front-haul or back-haul of the mobile data, the multigigabit technology offers a cost-effective migration path for the deployment of next-generation small cell and Wi-Fi technologies over legacy network infrastructure.
Phil Delansay is a co-founder of Aquantia. In 2009, he focused his efforts on the role of VP of business development in charge of investor relations, public relations, legal affairs, business strategy and patent activity. Prior to founding Aquantia, he held a number of management roles in network technology companies such as NEC, Japan, Alcatel, Lightera and Greylock Partners. He holds a doctorate in semiconductor physics from Orsay University, France.
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