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5G Vision With Converged Network Architecture

Wireless
Posted by James Donovan on 22 February 2017 Connect with James on LinkedIn Estimated reading time: 4 minutes

The 5G vision will be realized in the converged network in three fundamental ways: through densification, virtualization, and optimization of the network.

Densification

If 5G is really going to deliver speeds 10 or more times faster than 4G, reason dictates this will require more base stations in a given area—increasing the density of the network itself.

Mobile network operators (MNOs) have begun this process in their 3G and 4G networks, with increased sectorization and the addition of small cells. Regardless of how 5G is ultimately defined, it will require more densification across macro sites, in-building and within small cells.

Densification adds complexity to the network because it increases the number of cell borders, where interference becomes a problem and handoffs introduce the possibility of dropped connections. In a 5G world, networks will need to depend on intelligent, automatic spectrum allocation to maintain quality as well as speed.

Wireline infrastructure will also require upgrades to provide adequate fronthaul, backhaul, and power.

Virtualization

MNOs will need to virtualize much of their 5G infrastructure to effectively manage spectrum—and efficiently manage costs.

Several solutions and practices already exist to make this migration practical, including:

  • Centralized radio access networks (C-RANs), which will be the precursor to cloud radio access networks (also known as C-RANs). Centralized RAN involves moving baseband processing units (BBUs) from cell sites to a central location serving a wide area via fronthaul. This practice not only reduces the amount of equipment at the cell site but also lowers latency. In the coming evolution of cloud radio access networks, many BBU functions will be offloaded to commercial servers, essentially virtualizing the radio itself and greatly simplifying network management.
  • Network function virtualization (NFV), which guides the development of new core network architecture that will simplify the rollout of new services. NFV and software-defined networking (SDN)—deployed in conjunction with advanced analytic tools—will allow MNOs to automatically optimize their networks under policy control.
  • Cell virtualization, which extends the concept of virtualization beyond the core network to the airwaves. Inside buildings, cell virtualization will enable MNOs to manage multiple radio points within the footprint of a single cell, boosting capacity and eliminating inter-cell interference. C-RAN-enabled cell virtualization also gives operators the ability to greatly increase spectrum reuse—hence, boosting overall efficiency.
  • Virtual service instances, which reflect the need for 5G networks to support a diverse set of use cases. These virtual instances (or “network slices”) can serve different customers with different Quality of Experience (QoE) levels even though they may be sharing common computing, storage or connectivity resources.

Optimization

The third strategic component is to design and deploy for optimal performance. On a general level, this means increased efficiency throughout the converged network architecture – from spectrum efficiency to implementation of virtualized load-balancing, and from space-efficient small cells to energy-efficient backhaul. These measures are seen in such solutions as:

  • Mobile edge computing (MEC), which will serve the low-latency 5G IoT use cases such as augmented driving and the tactile internet. Placing cloud-computing capabilities at the edge of the mobile network involves many smaller data centers distributed closer to the cell sites—forming an edge cloud where intelligence can be placed closer to devices and machines. Content will become more complex and will require ultra-low latency—not just in the pathway (which 5G solves), but in the core data center. Moving all of this content to the very edges of the network solves the problem.
  • New power solutions, which are needed by 5G networks that have targets for energy efficiency as well as spectrum efficiency. It will be essential to learn how to get this power to sites in a practical, cost-effective and environmentally-responsible way. Power over Ethernet (PoE) is a promising technology for 5G devices in the IoT.

Frequency management in shared site equipment, which will require advanced self-organizing network (SON) capabilities in addition to core network architecture changes. New access network techniques such as massive MIMO (multiple inputs, multiple outputs) are required to deliver the 5G experience; RF beamforming and interference mitigation technologies are also critical.

Massive MIMO typically describes arrays of at least 64 antennas—often in bands above 2 GHz in the TDD spectrum. Massive MIMO will be deployed extensively in the centimeter and millimeter wave bands where the antennas become very small.

  • Time division duplex (TDD) modes, which will play a significant role in growing 5G deployments. 
  • Interference mitigation, which is needed to ensure robust data services, as increased complexity demands increase the signal-to-noise ratio (SNR). As stated in Shannon’s Law, the level of noise and interference in a wireless network determines the throughput capacity. MNOs must focus on ensuring a clean RF path through new technologies that reduce cell border interference, carefully sculpted transmission patterns, and network optimization.