This decision had consequences on the architecture itself but also on the way that the services were provided. It was therefore agreed that the EPC would not have a circuit-switched domain anymore and that the EPC should be an evolution of the packetswitched architecture used in GPRS/UMTS. When designing the evolution of the 3G system, the 3GPP community decided to use IP (Internet Protocol) as the key protocol to transport all services. It was therefore agreed that the EPC would not have a circuit-switched domain anymore and that the EPC should be an evolution of the packet-switched architecture used in GPRS/UMTS. Some network elements have evolved but the concept remains very similar. In UMTS (3G), this dual-domain concept is kept on the core network side. Therefore, the core network is composed of two domains: circuit and packet. In GPRS, the circuits still transport voice and SMS (in most cases). This offers more flexibility and efficiency. With this technology, data is transported in packets without the establishment of dedicated circuits. In GPRS, packet-switching (PS) is added to the circuit-switching. In GSM, all services are transported over circuit-switches telephony principally, but short messages (SMS) and some data is also seen. This circuit-switching mode can be seen as an evolution of the "two cans and a string". This means that circuits are established between the calling and called parties throughout the telecommunication network (radio, core network of the mobile operator, fixed network). In GSM, the architecture relies on circuit-switching (CS).
The EPC is the latest evolution of the 3GPP core network architecture. Incoming datacom services are therefore still relying upon the circuit switched core for paging. In UMTS the IP address is allocated to the UE when a datacomservice is established and released when the service is released. The access network in UMTS emulates a circuit switched connection for real time services and a packet switched connection for datacom services (black in figure 1).
#Peakhour no interfaces code#
To reach higher data rates in UMTS (Universal Mobile Terrestrial System) a new access technology WCDMA (Wideband Code Division Multiple Access) was developed. The first step towards an IP based packet switched (green in figure 1) solution was taken with the evolution of GSM to GPRS, using the same air interface and access method, TDMA (Time Division Multiple Access).
GSM was developed to carry real time services, in a circuit switched manner (blue in figure 1), with data services only possible over a circuit switched modem connection, with very low data rates. The main requirements for the new access network are high spectral efficiency, high peak data rates, short round trip time as well as flexibility in frequency and bandwidth.įigure 1.1: Network Solutions from GSM to LTE LTE (Long Term Evolution) or the E-UTRAN (Evolved Universal Terrestrial Access Network), introduced in 3GPP R8, is the access part of the Evolved Packet System (EPS). User demand for higher data rates and quality of serviceĬontinued demand for cost reduction (CAPEX and OPEX) Low complexityĪvoid unnecessary fragmentation of technologies for paired and unpaired band operation Need to ensure the continuity of competitiveness of the 3G system for the future LTE specifications are very stable, with the added benefit of enhancements having been introduced in all subsequent 3GPP Releases. Release 8 was frozen in December 2008 and this has been the basis for the first wave of LTE equipment. LTE (both radio and core network evolution) is now on the market.
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