PACKET MICROWAVE FOR METRO CELL BACKHAUL ENABLING A SEAMLESS EVOLUTION TO HETEROGENEOUS NETWORKS APPLICATION NOTE

PACKET MICROWAVE FOR METRO CELL BACKHAUL ENABLING A SEAMLESS EVOLUTION TO HETEROGENEOUS NETWORKS APPLICATION NOTE

TABLE OF CONTENTS Introduction / 1 Backhaul challenges for metro cells / 2 Getting wireless backhaul to the metro cell / 2 Scaling the macro cell microwave network / 4 Rapidly deploying metro cells / 4 The Alcatel-Lucent Packet Microwave Mobile Backhaul Solution / 4 Metro cell backhaul flexibility through 9500 MPR-s / 5 Microwave network scale / 6 Professional services for rapid metro cell deployment / 7 Conclusion / 8 References / 8 Acronyms / 8

The transition to higher capacity 3G and 4G/LTE networks and the introduction of small cells are the strategic tools that mobile network operators (MNOs) have at their disposal to keep pace with rapidly increasing mobile service demand. Small cells introduce new backhaul challenges because their optimal placement means that they will be deployed on street furniture, inside heavily populated buildings and on the sides of buildings. Leveraging existing macro cell sites to reach these small cell locations is an attractive approach to solve the challenges associated with small cell backhaul. This approach will introduce macro cell backhaul scaling challenges, including the scaling of bandwidth supported over scarce microwave spectrum that backhauls the majority of macro cells today. The Alcatel-Lucent Packet Microwave Mobile Backhaul solution addresses these challenges and allows for an efficient transition to heterogeneous networks. INTRODUCTION The transition to higher capacity 3G and 4G/LTE networks and the introduction of small cells are the strategic tools that mobile network operators (MNOs) have at their disposal to keep up with rapidly increasing mobile service demand. Small cells enable the delivery of capacity and coverage exactly where needed to relieve overloaded macro cell networks and deliver an enhanced Quality of Experience (QoE) to mobile subscribers. However, optimal placement of small cells means deployment on street furniture, inside heavily populated buildings and on the sides of buildings. These types of deployments introduce new backhaul challenges that must be overcome for the successful deployments of small cells and the heterogeneous networks they support. Metro cells are a subset of small cells that include MNO-managed small cells but exclude residential and enterprise femto cells. To scale mobile service capacity, it is estimated that three to ten outdoor metro cells will be used per macro cell. One widely anticipated approach for metro cell backhaul is to use metro cell optimized wireless devices to carry traffic to the nearest macro cell tower. ABIresearch expects that these types of wireless devices will be used to backhaul over 50 % of metro cell sites. [1] This type of deployment introduces backhaul challenges in the following areas: Selecting the right wireless metro cell backhaul technology Scaling macro cell backhaul network bandwidth Attaining the skills needed to successfully design and deploy end-to-end metro cell backhaul networks 1

Microwave technology is used to backhaul traffic for more than half of the macro cell sites worldwide. The reasons for this prominence are well known: in many cases microwave allows for faster and more cost-effective deployment of backhaul capacity than do wireline alternatives. Ethernet packet-based microwave connections are increasingly replacing legacy PDH E1/T1 and SDH/SONET microwave connections. According to Heavy Reading, packet-based backhaul is expected to be deployed for greater than 80 % of all backhaul connections by 2015. [2] Metro cells are designed for packet-based backhaul, and their introduction will further accelerate an evolution to packet microwave. This paper reviews extensions to the successful Alcatel-Lucent Packet Microwave Mobile Backhaul solution that address the backhaul challenges for metro cells. BACKHAUL CHALLENGES FOR METRO CELLS Selecting an optimal site for metro cell deployment is a tradeoff among Radio Access Network (RAN) performance, site leasing costs and backhaul availability. Extending backhaul to metro cell sites from MNO established macro cell towers is an attractive backhaul option because it leverages established macro cell sites and associated costs. Running fiber between metro cell and macro cell locations is often prohibitively expensive, so has led to the introduction of metro cell optimized wireless backhaul devices. However, deploying these types of devices comes with a specific set of challenges: Selecting the optimal wireless technology Scaling the macro cell backhaul network, including microwave links, to handle increased metro cell packet demands Acquiring the backhaul skills and resources to rapidly and cost-effectively deploy metro cells Getting wireless backhaul to the metro cell To deliver mobile subscriber capacity where it is needed, metro cell sites need to take advantage of street furniture such as lamp posts and the sides of buildings. Metro cell deployment numbers and their locations, together with the number of subscribers they support, make metro cell deployments different from macro cell deployments in the following ways. Environmental differences To be optimally located, a metro cell site needs to be visually unobtrusive to avoid rejection from the public. The metro cell site can t always be placed in a protected indoor environment, so metro cell backhaul equipment must be able to withstand a harsh outdoor environment. Optimal metro cell placement often precludes line-of-sight (LOS) link engineering between the metro cell and the macro cell locations. Non-line-of-sight (NLOS) technologies are also required to get around LOS obstacles such as trees and building structures. Cost-of-deployment differences A metro cell site must be set up with minimal OPEX, it should be able to be constructed by a single person with one visit to the cell site, and it can t require precise antenna alignment schemes to support backhaul. Frequency licensing fees and the related interference studies should be minimized. 2

These differences have provided the impetus for new generation of small form factor wireless systems using frequency bands that fall outside the licensed frequencies typically used for macro cell backhaul. Of these frequency bands, two are emerging with the strongest potential to support metro cell backhaul requirements for availability and performance. 60-GHz frequency band The advantages of the 60-GHz frequency band are: high capacity, low latency, wellunderstood LOS link engineering, high immunity to interference, and license-free operation. Link transmission rates as high as 1 Gb/s, with sub-50 microsecond latency can be implemented using this band. These latency characteristics are consistent with macro cell microwave backhaul frequencies that are used today, and they enable the 60-GHz band to address the most demanding 2G, 3G and/or 4G/LTE backhaul Service Level Agreements (SLAs). The high capacity that this band offers allows it to be positioned for end metro cell sites and the aggregation of several metro cell sites using various network topologies. This band also presents a very narrow beam, making it easier to mitigate interference in an unlicensed domain. Potential interference can only occur with another 60-GHz channel if it is tightly squeezed into the same narrow sector. The high oxygen absorption characteristics of this band limit maximum link distance to 1 km, allowing several 60-GHz links to be densely packed into a small area without interference issues. These characteristics enable maximum network bandwidth using low-cost unlicensed bands. Unlicensed band operation also avoids licensing delays and associated costs, making it faster to deploy and less expensive to operate than licensed frequencies. This band is widely available in many countries: United States, Canada and Brazil (57-64 GHz) Europe (59-66 GHz) South Africa, Australia and China (59-64 GHz) Japan (59-66 GHz) New Zealand and Korea (57-64 GHz) Sub-6 GHz frequency band The sub-6 GHz frequency band supports licensed and unlicensed NLOS operation to address deployments where obstacles to LOS technologies exist. This band has the characteristics required to operate in the high interference and severe multipath conditions typically encountered with metro cell dense urban deployments. However, implementations that leverage this band typically introduce additional delay and delay variation when compared to pure LOS technologies. To avoid additional delay and delay variation, careful engineering is typically required to meet backhaul SLAs. Bandwidth capacities supported by implementations using this band typically require deployment at end metro cell sites rather than the aggregation of many metro cell sites. Sub-6 GHz implementations typically support point-to-point and point-to-multipoint configurations. Point-to-multipoint implementations leverage a common hub site antenna to communicate with individual spoke endpoints to provide cost savings over deploying multiple point-to-point links. 3

Scaling the macro cell microwave network The introduction of metro cells will accelerate scaling pressures on macro cell microwave backhaul networks. This pressure will lead to the development of increased higher order modulation schemes and regulatory bodies allowing for wider microwave channels to support higher bandwidth capacities (such as the recent FCC rulings allowing wider channels in the 6-GHz and 11-GHz bands). While these initiatives help to scale microwave bandwidth, they are insufficient on their own to increase microwave link capacity to the required levels. It is becoming increasing difficult to realize backhaul payload capacity gains when moving to higher order modulation rates due to degraded link performance and/or related antenna costs. Support for wider microwave channel width can also adversely impact microwave performance and increase deployment costs. Acquiring adjacent channels to create wider channels may also be difficult or impossible in congested urban areas where much of the increased capacity is required. So, while support for higher order modulation and wider channels can help address increasing bandwidth demands on microwave links, they are not without issues, and are insufficient on their own to increase microwave link capacity to the required levels. A broader approach is required to thoroughly scale scarce microwave spectrum an approach that leverages microwave channel bonding techniques, including: The bonding of channels with different polarizations at the same frequency Data traffic compression Optimal multiplexing of backhaul traffic with adaptive modulation-aware Quality of Service (QoS) mechanisms Advanced packet networking Rapidly deploying metro cells MNOs and backhaul transport providers (BTPs) realize they need to evolve their networks to packet-based backhaul to support the addition of metro cells to the macro cell network and simplify the operation of their networks. However, these operators may not have the expertise or resources to support this transition in the deployment timeframes required. Packet backhaul expertise and supporting tools are required to determine the right backhaul approach to be used and are critical to the design of a reliable, evolvable and robust end-to-end backhaul network. THE ALCATEL-LUCENT PACKET MICROWAVE MOBILE BACKHAUL SOLUTION As part of the Alcatel-Lucent Packet Microwave Mobile Backhaul Solution, the Alcatel-Lucent 9500 Microwave Packet Radio (MPR) has quickly established a packet microwave leadership position by supporting features that enable: 2G, 3G and 4G/LTE backhaul over a common packet network Superior spectrum performance Service-aware QoS Synchronization distribution flexibility. 4

The Alcatel-Lucent Packet Microwave Mobile Backhaul solution (see Figure 1) has provided a 4G/LTE mobile backhaul transformation capability for MNOs and BTPs globally, and has been extended with the metro cell backhaul flexibility, scalability and rapid time-to-deploy capabilities required to support the backhaul of heterogeneous networks consisting of metro cells and macro cells. Figure 1. Alcatel-Lucent Packet Microwave Mobile Backhaul solution Metro cell sites (9500 MPR-s) 60 GHz Sub-6 GHz NLOS 5.8 GHz 6-42 GHz 60 GHz 80 GHz Metro aggregation/transport Sub-6 GHz P2MP Microwave hub site 9500 MPR Mobile controllers/ gateways Macro cell tail site (9500 MPR) 5.8 GHz 6-42 GHz 60 GHz 80 GHz Metro cell backhaul flexibility through 9500 MPR-s Rapidly deploying cost-effective backhaul to optimal metro cell locations is critical to maximizing RAN performance and addressing mobile subscriber QoE. Alcatel-Lucent has enhanced its 9500 MPR portfolio deployment flexibility with the following metro cell backhaul options: Sub-6 GHz NLOS licensed and unlicensed options that can support up to 200 Mb/s net aggregate throughput in point-to-point or point-to-multipoint configurations 60-GHz unlicensed LOS options that can support full-duplex gigabit capacities for aggregating several metro cells These 9500 MPR-s rugged small form factor options maximize spectrum performance and are powered using Power over Ethernet (PoE) technology. At metro cell sites they are directly connected through Ethernet to metro cells or related backhaul equipment. At macro cell sites they are connected through Ethernet to 9500 MPR devices to support subtending backhaul from macro cell sites to metro cell sites. 5

The 9500 MPR management platforms enable rapid provisioning of end-to-end backhaul services, including over 9500 MPR-s links, eliminating the need to individually configure each device in the service path. This reduces the complexity and risk associated with provisioning complex services and provides support for Fault, Configuration, Accounting, Performance and Security (FCAPS) management. With these metro cell backhaul focused additions, Alcatel-Lucent continues to offer the most comprehensive end-to-end portfolio for microwave-based mobile backhaul. Microwave network scale To address increasing 3G and 4G/LTE macro cell bandwidth capacity requirements, operators globally are evolving their traditional microwave networks to packet microwave networks. The addition of metro cells to the macro cell network will further accelerate the evolution to packet microwave networks and require them to constantly scale to address increasing metro cell backhaul demands. As previously mentioned, initiatives in the areas of increased higher order modulation and the widening microwave channels will help scale microwave to meet capacity demands. However, these initiatives are insufficient on their own to meet the required demand. The 9500 MPR goes beyond these initiatives to deliver the required scalability with support for the following features: Intelligent packet compression: Algorithms that can increase microwave bandwidth utilization by as much as 300 % High capacity microwave channel bonding: The ability to seamlessly bond radio channels into higher capacity microwave connections, including support for bonding channels with different polarizations at the same frequency Advanced packet networking: Multiservice-aggregation support allows 2G, 3G and 4G/LTE to share a common packet-based backhaul without having to strand bandwidth between TDM and packet domains a common issue associated with hybrid microwave systems High-capacity microwave topology support with up to 24 microwave connections at dense microwave hub sites, including the ability to bond up to 4 radio channels in each of these directions, utilizing a compact 2-RU, power-efficient, indoor Microwave Services Switch (MSS) Standards-based ITU G.8032v2Ethernet networking options that allow for maximum network bandwidth utilization and offer sub-50 millisecond network reliability capabilities to protect against network failures Service-aware QoS: Optimal scheduling of packet traffic to stay within SLA bounds for backhaul delay, delay variation and loss High performance adaptive modulation capabilities that maximize the use of high-order modulation when adjusting to changing radio propagation conditions Patented synchronization algorithms based on radio symbol rate: Algorithms that do not consume precious over-the-air bandwidth and are also totally independent of network load. These algorithms complement end-to-end synchronization distribution options based on: Synchronous Ethernet (SyncE) IEEE 1588v2 Precision Time Protocol SONET/SDH 6

A full range of macro cell backhaul frequency options from 6 GHz to 80 GHz are also available to scale network capacity. To further maximize spectrum options for macro cell backhaul, the 9500 MPR supports carrier grade 5.8-GHz unlicensed operation. This unique 5.8-GHz option is supported on a compact transceiver that can universally address any microwave deployment. It enables rapid macro cell site deployment with the ability to seamlessly transition to licensed band operation if or when required. Figure 2 shows the Alcatel-Lucent 9500 MPR portfolio. Figure 2. Alcatel-Lucent 9500 MPR portfolio: Enabling a seamless evolution to heterogeneous networks MACRO CELL BACKHAUL METRO CELL BACKHAUL CELL SITE DEPLOYMENT FLEXIBILITY Outdoor Common MPT transceiver for full outdoor and split-mount Outdoor 18 cm 7 in 27 cm 10.6 in 60 GHz Sub 6 GHz NETWORK SCALABILITY 9500 MPR COMPACT INDOOR OPTIONS 9500 MPR-S MSS-1 (0.5 RU) MSS-4 (1 RU) RAPIDLY DEPLOY MSS-8 (2 RU) 9500 MPR Professional services for rapid metro cell deployment The 9500 MPR metro cell and macro cell backhaul solutions are supported by Alcatel-Lucent s professional services. Design and business case analysis tools that leverage proven Bell Labs network modeling algorithms are used to support the following backhaul professional services: Business case analysis to determine the right backhaul approach Design services that ensure reliable, evolvable and robust backhaul These professional services can be used to instantly gain the skills required to successfully design and rapidly deploy packet backhaul for metro cells and heterogeneous networks. 7

CONCLUSION The transition to higher capacity 3G and 4G/LTE networks and the introduction of metro cells are the strategic tools that MNOs have at their disposal to keep pace with rapidly increasing mobile service demand. Metro cells introduce new backhaul challenges because their optimal placement means they will be deployed on street furniture, inside heavily populated buildings and on the sides of buildings. Leveraging existing macro cell sites to reach these metro cell locations using metro cell optimized wireless technologies is an attractive approach to solve the challenges associated with metro cell backhaul. This approach will introduce macro cell backhaul scaling challenges, including the scaling of bandwidth supported over scarce microwave spectrum that backhauls the majority of macro cells today. Just as the 9500 MPR has enabled the optimal deployment of large macro cell networks, new product extensions deliver the metro cell site deployment flexibility, microwave network scalability and rapid deployment support to allow for an efficient transition to heterogeneous networks. REFERENCES [1] ABIresearch, Backhaul Options for Outdoor Small Cells. Nick Marshall, Principal Analyst, Mobile Networks and Aditya Kaul, Practice Director, Mobile Networks: September 10, 2012. [2] Heavy Reading, Ethernet Backhaul Quarterly Market Tracker: January 2013. ACRONYMS 2G Second-Generation Mobile Network NLOS non-line-of-sight 3G Third-Generation Mobile Network OPEX operating expenditures 4G Fourth-Generation Mobile Network PDH Plesiochronous Digital Hierarchy BTPs backhaul transport providers PoE Power over Ethernet FCAPS Fault, Configuration, Accounting, RAN Radio Access Network Performance and Security RU Rack Unit IEEE ITU LOS LTE MNO MPR Institute of Electrical and Electronics Engineers International Telecommunication Union line-of-sight Long Term Evolution mobile network operator Microwave Packet Radio SDH SLA SONET SyncE TDM QoE Synchronous Digital Hierarchy Service Level Agreement Synchronous Optical Network Synchronous Ethernet Time Division Multiplexing Quality-of-Experience MSS Microwave Services Switch www.alcatel-lucent.com Alcatel, Lucent, Alcatel-Lucent and the Alcatel-Lucent logo are trademarks of Alcatel-Lucent. All other trademarks are the property of their respective owners. The information presented is subject to change without notice. Alcatel-Lucent assumes no responsibility for inaccuracies contained herein. Copyright 2013 Alcatel-Lucent. All rights reserved. M2012125516 (February)