July 30, 2015 | by Wayne Smith

The Evolution to 5G Wireless: Part II

A dIn Part #1 of this series, we addressed who is promoting 5G, the societal trends driving demand for it, its development timeline and a guess at the IMT’s 2020 5G Vision. This article will address the expected requirements for 5G and some potential technologies necessary to meet them.

5G Requirements

The overall goal of the following requirements is to provide the user a seamless, mobile communications experience. The items listed below are currently being discussed in several white papers, brochures and presentations that can be found by searching the Internet. Note the listing below is not in any specific order.Spectral efficiency (the amount of data that can be transmitted over a specific bandwidth) will be 2.5X or greater than 4G. Expected required spectral efficiency for downloads will be about ten bps/Hz and upload efficiency will be around five bps/Hz.Peak download data rates will be around 10 Gbps and upload rates will be in the 1 Gbps range.The network will have very high capacity to manage between 500 billion and one trillion end devices. It must be able to support data volumes 1000X or greater than 4G networks. A major component of these devices will be massive machine to machine (M2M) connections.The turn-around latency will be lowered to approximately one millisecond which is about one-fifth 4G latencies.Handover latency will be reduced to about 10 milliseconds which is about one-fifth 4G handover latency.Devices must support very high mobility with robust connections at speeds between 350 Km/hr to 500 Km/hr.Radio cells must become edgeless with context aware devices that are involved in signal selection decisions. This means some network intelligence will migrate to the user device.Network devices are expected to consume 1/10 the energy of 4G network devices. IoT sensing devices will have battery lives approaching 10 years. Infrastructure equipment will have similar stringent energy requirements.The 5G network will support very dense access points, dense HetNets and 1000X the connectivity requirements of the 4G network.The network will be ultra-reliable with 99.999% reliability which means the typical user should never have any communication failure like a dropped call or bad reception.It will support device to device (D2D) connections for emergency and mission critical private requirements. D2D connections are being defined in the 3GPP’s Release 13 for 4G networks. This will be an enhancement to those standards.It will support dynamic spectrum allocation schemes that will enable different frequency band sizes as well as aggregating component carriers from non-adjacent frequency bands.It will utilize extensive cloud computing and virtual network computing technologies. This moves the intelligence of the network from the RAN to the cloud which is powered by general purpose computers located in data warehouses.It will be designed to reduce CAPX and OPEX expenditures to 1/5th those of similar functionality for the 4G network. Much of this is based on using cloud computers, virtual networks, self organizing networks, etc.It will be an all-open packet architecture.Potential 5G Technologies

Below is a listing of many of the technologies and challenges that must be addressed, developed and implemented in order to make 5G a reality. Once again, they are in no specific order.

More radio spectrum will be necessary. This spectrum will likely range from 3 GHz to 100 GHz. Decisions must be made on how this spectrum is divided and allocated.New radio access technologies must be developed that will dynamically manage aggregation of the allocated bands.Use mmWave technologiesUse modulation schemes like 256 QAMManage the “edgeless” radio cellMassive MIMO technologies (64 plus antennas) will be necessary.The network will have to manage dense HetNets, ultra-dense cells, unlicensed WiFi frequencies, and possible frequency re-use schemes.Enhanced D2D radio access technology will be necessary.Massive machine to machine connections must be supported.There will be greater application of software defined networks (SDN) and network functions virtualization (NFV).Front-hall and back-hall technologies will converge into the same technology.There will be extensive use of self organizing network technologies.There must be improvements to fiber backbones.

Well, that is a partial list of current and new technologies. It will be interesting to see what technologies are actually developed and implemented. You can understand why 5G is an international affair involving governments, universities, trade associations, and private companies. It is truly an “extraordinary project” that could impact world societies as much as the telephone itself did.