5G Energy Efficiency Explained

This article describes the various 5G technologies and architectures that are being deployed to increase network energy efficiency and reduce overall power consumption.

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The Challenge

In the communications space, power consumption and the resulting energy-related pollution are becoming major operational and economical concerns. The exponential increases projected in network traffic and the number of connected devices makes energy efficiency increasingly important. Thus, increasing energy efficiency in mobile networks will reduce the costs of capital and operational expenditures.

THE GOAL

5G design requirements specify that energy use be reduced to 10 percent of current 4G networks. This includes reducing power requirements for radio base station antennas, as well as client devices such as smartphones and IoT devices to extend battery life.

Traditional mobile networks spend about 15 to 20 percent of overall power consumption on actual data traffic. The unused energy is wasted. Increasing energy efficiency has a huge potential to harness wasted power and deploy new technologies, which would further reduce power consumption.

New technologies are being deployed in Mobile network infrastructures to reduce power consumption. These include cloud and virtualization technologies, new efficient antenna hardware, 5G small cell network architectures and more efficient network protocols.

The goal for 5G devices is to increase battery life to:

  • At least three days for smartphones
  • Up to 15 years for cellular IoT devices

1 – Sleep Modes

During gaps in network activity, the base station can reduce energy consumption by going into sleep mode. New base station electronics can enter sleep mode during very short gaps. Even in high-use mobile networks, base station utilization usually does not exceed 20 percent.

Base stations consume 80 percent of the power in a mobile network infrastructure and in any 24-hour period, most base stations remain idle. 5G base stations can go into sleep mode during this idle time. They can go into sleep mode quickly and for as long as possible.

2 – Higher Network Data Rates

5G networks have higher data throughput and reduced packet latency. Higher data rates mean data is transferred in in shorter periods of time. This creates longer periods in which the network connection between the client and the base station is idle. These Idle periods allow for longer periods of sleep mode.

3 – NEW NETWORK PROTOCOLS

New 5G network protocols reduce power consumption:

  • Data packet payloads are compressed, reducing traffic volume
  • User traffic and control traffic is separated, reducing the network chatter on the user data networks

The reduced traffic and elimination of control packets creates larger idle periods, and therefore, longer periods of sleep mode.

The Multipath Transmission Control Protocol (MPTCP) increases network efficiency and reduces packet retransmits, reducing overall energy consumption.

4 – Full Duplex

Advances in signal-processing electronics now support full-duplex network communications on the same frequency. Earlier technologies required different frequencies to transmit and receive data simultaneously.

Full-duplex passive suppression and digital cancellation (PSDC) communication mode is more energy-efficient than the plain passive suppression full-duplex mode. Experimental results show that, the full-duplex DSDC mode achieves up to 40 percent increased energy efficiency compared to half-duplex.

5 – Massive MIMO Antennas

Multiple input multiple output (MIMO) is a technology that uses multiple antennas configured in a two-dimensional phased array. The antenna system is attached to a base station and controls the transmission and reception of radio signals.

Massive MIMO systems are expanded MIMO systems with up to several hundred antennas and can handle large volumes of network throughput and support large numbers of client connections.

Multiple antennas working together have several advantages:

  • Multiple parallel antennas have higher gain
  • They are resistant to intentional jamming
  • There are more paths to the 5G client, providing stronger signal strength
  • More parallel antennas can serve a larger number of users
  • Antenna arrays can better identify 5G client physical locations
  • Arrays can also track mobile clients and direct the transmission beam at the client, following the client movements and maintaining network connectivity

Beamforming is a technology that can direct radio transmission signals in a specific direction. This increases the channel efficiency, data rates, reduces interference and focuses radio energy directly at the client devices.

Since the massive MIMO antenna and base station systems communicate with remote clients using a focused beam, the wireless protocols can calculate the minimum power required for communication. This reduces the energy consumption for wireless energy transmissions for both the base station and the client devices. As a result, 5G networks using beamforming consume about four times less power than comparable 4G networks.

6 – Small Cells

A mobile network cell includes the antenna, base station and the physical area that is serviced by the cell. A standard cell is called a macro cell. A small cell is just a smaller version of a macro cell and is available in several sizes and powers: micro cells, pico cells and femtocells. Small cells are either installed inside buildings or outside in densely-populated areas.

Small cells expand and scale 5G networks to meet demand, providing:

  • Additional capacity for users and network connections
  • Network bandwidth and throughput
  • Lower network latencies
  • Reduced signal interference
  • Radio signal coverage in locations that are not in line-of-site with cell towers
  • Reduced network transmission power requirements and thus increased client battery life

Reduced Distance to Base Stations

The power required to communicate between clients and 5G base stations increases the further the signal has to be transmitted. Since small cell base stations are deployed in close proximity to client devices, it significantly reduces power consumption by both the base stations and the 5G client devices.

Increased Network Density

Small cells with massive MIMO antennas can serve many more devices at the same time. Each device is multiplexed over the same space and frequency. This spatial multiplexing uses the same channel to serve multiple devices. The energy consumption is also shared among multiple users or devices.

As an example, when 10 devices are multiplexed, the energy consumption of each device is one-tenth, or an energy efficiency of 10x.

7 – Large Efficient Spectrum

Spectral efficiency and scheduling algorithms were introduced in the 5G NR specifications. The increase in spectral efficiency due to various features and scheduling algorithms ensures that 5G can have higher throughput compared to its predecessors.

 

typical scheduling used by 4G

 

In the diagram above, the typical scheduling is used by 4G and has a large number of control codes in stream. As a result, the overhead is about 10 to 20 percent and increases with higher-frequency transmissions.

The bottom uses the new 5G slot aggregation scheduling and greatly reduces traffic overhead and energy consumption.

9 – Network Virtualization: NFV and SDN

One of the key architectural requirements specified for 5G infrastructures is that all core network systems be based on software virtualization. Network infrastructures have traditionally included physical purpose-built appliances, which are less flexible to manage, deploy and scale.

Network Functions Virtualization (NFV) is a network architecture based on Virtual Network Functions (VNF). Network functions include any system that provides network functions like network routing, packet processing, security and many others.

Software Defined Networks (SDN) are virtualization technologies that abstract physical networks to virtual network structures. Virtual networks appear and behave like physical networks and have all the advantages of other virtualization technologies.

NFV and SDN technologies enable:

  • Better infrastructure scaling
  • Lower computational redundancy
  • Fewer hardware systems

This reduces the overall energy consumption.

How A10 Networks Can Help

A10 Networks provides products for high-performing network and security systems that process millions of concurrent sessions in real time. A10 Networks’ customers include the largest network carriers and cloud service providers in the world.

The company’s portfolio of products is broad and covers end-to-end network service provider infrastructures from network-edge computing, distributed packet-core processing and central-office infrastructures to public clouds.

This broad set of products from a single vendor reduces deployment, operations and management costs, therefore reducing TCO.

A10 Networks has unique competitive advantages for 5G infrastructures:

  1. Portfolio of service provider products
  2. High-performance VNFs
  3. In-process service function chaining
  4. VNF scale-out clustering
  5. Cloud-optimized architecture
  6. Industry-standard hardware server optimizations

A10 Networks white paper: Modernize Your 4G/LTE Network NOW for 5G Success

References

Nokia 5G Energy Efficiency white paper: https://gsacom.com/paper/5g-network-energy-efficiency-nokia-white-paper/

ETSI Energy Efficiency of 5G: https://docbox.etsi.org/Workshop/2017/20171123_ITU_ETSI_ENV_REQ_5G/S01_PART1/5G_EE_ASSESSMENT_ETSIEE_ITUTSG5_BOLDI.pdf

3GPP Study on Energy Efficiency Aspects of 3GPP Standards : https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3062