Tabula's ABAX family of 3PLDs addresses a wide variety of wireless applications including RF signal processing and baseband processing and is particularly well suited to meet the challenges of next generation LTE and WiMax networks.
The wireless industry has undergone tremendous changes and is expected to continue to evolve with major changes in the near future as 4G wireless technology is deployed. The primary drivers for the demand of new platforms and technologies are mobile data applications and the higher bandwidth requirements such applications require.
The wireless infrastructure can be partitioned into two major segments, common for all generations of wireless technologies.
- Radio Access Network (RAN
- Core Network (CN)
Different portions of the wirless infrastructure undergo equipment changes as wireless service providers upgrade their networks from one generation to the next. Some portions of the network may be reusable while other portions may require completely new equipment, all of which depends on the particular wireless technology being adopted. Figures 1 to 3 illustrate the required changes in infrastructure equipment as the network evolves from 2G to 4G.
Figure 1 depicts the network elements required for both 2G (GSM) and 2.5G (EDGE). 2G wireless is the technology intended for voice applications. It improved upon the first generation of wirless technology (AMPS - analog voice) by providing digitized voice. For data applications, 2.5G technology such as EDGE was introduced. With reference to Figure 1, the network elements denoted by blue represent the 2G infrastructure. In the transition from 2G to 2.5G, packet data capabilities are added to the network by upgrading two sections of the network. First, the Radio Access Network is upgraded to GERAN, which is essentially an air interface modulation format change, and is often acoomplisdhed by a software upgrade. Thus the BTS and BSC hardware can be resused. A new network element, the PCu (Packet Control Unit) is added into the RAN which handles all packet data and forwards it to the Core Network. Next, the GPRS Core Network, which handles all the packet data, is introduced into the infrastructure. The new network elements for the 2.5G network are denoted by red in Figure 1.
In the transition from 2.5G to 3G, only the RAN portion of the network is required to be upgraded. The upgrade from 2.5G GERAN to 3G UTRAN, denoted by red in Figure 2, involves replacing all BTS with NodeB network elements and replacing all BSC with RNC network elements. 3G UMTS reuses the previous generation circuir switched infrastructure for voice applications (MSC, HLR/VLR) and also reuses the 2.5G GPRS packet switching infrastructure (SGSN, GGSN) for packet data applications. Thus the Core Network is not required to be upgraded.
It should be noted that the sheet amaount of data expected to traverse the 3G infrastructure will increase substantially. As a result, the transport capacity of the RAN backhaul, connecting the remote cell site nodes (BTS, NodeB) to the central site nodes (BSC, RNC), may require an upgrade. Bonding multiple T1/E1 lines using ATM IMA (Asynchronous Transfer Mode Inverse Multiplexing) is a common approach to upgrading the RAN backhaul network for 3G networks.
In the transition from 3G to 4G, both the RAN and the Core Network need to be upgraded. The network elements required for the 4G network are depicted in red in Figure 3.
In the RAN, the 3G NodeB network elements are replaced with 4G eNodeB. Notice that 4G RAN (aka LTW) has a simpler architecture and consists of a single hierarchy containing only eNodeB elements. Some of the features normally implemented by the 3G RNC have been pushed down into the eNodeB, and some of the RNC features have been brought into the 4G Serving Gateway or into the Mobility Management Entity (MME).
In the Core Network, the entire infrastrcuture needs to be replaced. The older 3G network is an overlay network, with separate and distinct equipment handling only voice circuir switching and distinct equipment handling only packet data. In addition, by historical development, the 3G GPRS Core Network is largely based on ATM technology. The architecture for the 4G Core Network (aka EPC) is specified to be a simplified and flatter "all-IP" network, with all applications - voice, video and data - running over this common IP network. Thus the migration from 3G to 4G requires completely new infrastructure equipment in the Core Network.
The RAN backhaul also needs to be upgraded since the bandwidth capabiloties of 4G will be at least an order of magnitude greater than that for 3G. Continuing to use bonded T1/E1 lines is unattractive. Given that the bandwidth granularity for T1/E1 is 1.5Mbps/2Mbps, an excessive number of T1/E1 lines would be required to support 4G backhaul bandwidth which may be on the order of 1-2Gbps. Newer backhaul technology such as Carrier Ethernet may be more attreactive from an economic cost-per-bit point of view.
The industry standards for 4G technology are still being developed today. Only as of December 2008, have the standards for LTW and EPC (3GPP Release 8) been locked down. It is expected that many technology changes may continue to occur on the 4G network before it reaches a state of maturity.
