LTE
Revolution and Evolution
LTE
With Long Term Evolution (LTE) comes a new radio platform technology to mobile radio access networks that will revolutionize mobile broadband usage, allowing mobile operators to achieve even higher peak throughputs than HSPA+ in higher spectrum bandwidth. Work on LTE began at 3GPP in 2004, with an official LTE work item started in 2006 and a completed 3GPP Release 8 specification in March 2009.
LTE is part of the GSM evolutionary path beyond 3G technology, following EDGE, UMTS, HSPA (HSDPA and HSUPA combined) and HSPA Evolution (HSPA+). Although HSPA and its evolution are strongly positioned to be a dominant mobile data technology for the next decade, the GSM family of standards must evolve toward the future. HSPA Evolution will provide the stepping-stone to LTE for many operators. The overall objective for LTE is to provide an extremely high performance radio-access technology that offers full vehicular speed mobility and that can readily coexist with HSPA and earlier networks. Because of scalable bandwidth, operators will be able to easily migrate their networks and users from HSPA to LTE over time. For carriers that have deployed CDMA2000, LTE is a better upgrade path to enabling new high bandwidth mobile applications as even with EVDO, the data rates supported are well below 10Mbps. This is drivng the CDMA carriers to migrate to LTE sooner than the GSM carriers.
LTE assumes a full Internet Protocol (IP) network architecture and is designed to support voice and data in the packet domain. It incorporates top-of-the-line radio techniques to achieve performance levels beyond what will be practical with CDMA approaches, particularly in larger channel bandwidths. However, in the same way that 3G coexists with second generation (2G) systems in integrated networks, LTE systems will coexist with 3G and 2G systems. Multimode devices will function across LTE/3G or even LTE/3G/2G, depending on market circumstances.
Market Drivers
Global mobile subscriber base reached 4 billion in December last year. Mobile growth has been truly phenomenal specially in the last 5 years. Though voice has been the primary driver fueling this revolution, data transmission has also seen significant growth over the last couple of years. There is a continuous need for more and more bandwidth in order to enable more and more rich multimedia services. To cope up with the industry requirements, there has been a continuous uptrend in the mobile technologies too starting from GSM —> GPRS —> Edge —> HSPA —> HSPA+ and similarly from CDMA2000 —> EVDO Rev 0 —> EVDO Rev A —> EVDO Rev B. Every new technology brings in a significant higher data rate in order to enable more and more multimedia services.
Mobile subscribers are already changing their behavior on how they access the Internet, looking to access much more diverse content that includes a heavy dosage of video. Even today a single high-end smart phone (such as an iPhone or Blackberry) generates more data traffic than 30 basic-feature cell phones, and a laptop air card generates more data traffic than 450 basic-feature cell phones. And smart phone sales are soaring around the world versus feature phones even before they reach "free phone" status from mobile operators.
Benefits of LTE
LTE promises higher data speeds to mobile users, but it also includes an evolution of core mobile networks from circuit-switched to packet-switched technologies. This results in an overall simplification of the entire mobile network topology as seen in the diagram below. In this environment the mobile network is an all IP network that includes a re-tooling of radio access (LTE) and core network (Evolved Packet Core — EPC) elements into a more simplified network topology (sometime referred to as Service Architecture Evolution — SAE) that facilitates intra and inter network connectivity while significantly decreasing CapEx, OpEx, and NetEx for the mobile operator.
Technology Requirements
LTE Network Architecture
The LTE/EPC architecture is a comprehensive mobile network architecture that covers multitude of network elements. These are the key network elements in an LTE/EPC network:
The LTE/EPC architecture is a comprehensive mobile network architecture that covers a multitude of network elements. These are the key network elements in an LTE/EPC network:
- The Mobility Management Entity (MME) is the key control-node for the LTE access network. It is responsible for idle mode UE (User Equipment) tracking and paging procedure including retransmissions. It is involved in the bearer activation/deactivation process and is also responsible for choosing the S-GW for a UE at the initial attach and at time of intra-LTE hand over involving core network node relocation.
- Serving and PDN Gateways (S-GW and P-GW) - The S-GW acts as a local mobility anchor, forwarding and receiving packets to and from the eNB where the UE is being served. The P-GW, in turn, interfaces with the external PDNs, such as the Internet and IMS. It is also responsible for several IP functions, such as address allocation, policy enforcement, packet classification and routing, and it provides mobility anchoring for non-3GPP access networks.
- eNodeB (or eNB) merges the functionality of the RNC and Node B in a 3G mobile network to achieve reduced latency with fewer hops in data path as well as distribution of RNC processing load into multiple eNBs. The eNB is responsible for header compression, ciphering and reliable delivery of packets. On the control plane, functions such as admission control and radio resource management are also incorporated into the eNB.
Radisys ATCA Solutions for LTE
The commercially proven, ATCA open hardware specification is designed from the ground up to meet the demanding need of evolving networks and video services with service delivery packaging that provides unparalleled scalability, responsiveness, modularity, and flexibility to meet ever increasing network requirements.
Radisys provides Applicaton Ready ATCA Platforms for LTE EPC including MME, Serving Gateway and Packet Gateway. RadiSys offers the broadest portfolio of ATCA products that includes switching, x86 based, packet processing and media processing boards with latest silicon technologies to deliver optimal configurations for LTE EPC. RadiSys ATCA Application ready platform also includes integrated chassis, OS, diagnostics, system manager, and high availability middleware. This platform has already enabled 35+ telecom applications and is now configured for robust performance in LTE EPC for both 10G and 40G technologies.
Below, is a typical configuration one can develop using RadiSys Promentum Platform Elements:
- As a sample configuration, LTE EPC solutions can be built using RadiSys Promentum 2U/5U/12U ATCA System (includes ATCA-2210 switch), ATCA-7220 Packet Processing Module for functions such as packet forwarding and tunneling, policy enforcement, and lawful intercept while ATCA-4500 CPU module may be used for mobility management/IP address allocation, accounting and charging, and lawful intercept. ATCA 4.0 — evolution to 40G allows this architecture to smoothly scale to higher performance as EPC demands grow.
In order for the 4G network demands to be met, these network elements will need to scale within a compact footprint for 4G services to be deployed quickly, economically, and with a high degree of serviceability. This means modularity and density per module in some of the key network elements is a key requirement. RadiSys Promentum platform delivers this and more. Learn more about Promentum Application Ready Platforms and building blocks at:
