ABSTRACT

Long-Term Evolution (LTE) complements the achievement of HSPA with better peak information quotes, decrease latency and an enhanced broadband experience in high-call for areas. This is completed with the usage of wider-spectrum bandwidths, OFDMA and SC-FDMA air interfaces, and superior antenna strategies. These strategies enable excessive spectral efficiency and an first rate person enjoy for a huge range of converged IP offerings. To take full advantage of these broadband get admission to networks and to permit the co-life of multiple technologies via an green, all-ip-packet architecture, 3GPP™ implemented a new center network, the developed packet center (EPC). EPC is deliberate for 3GPP Release 9 and is meant for use with the aid of numerous access networks which includes LTE, HSPA/HSPA+ and non-3GPP networks. The developed packet system (EPS) incorporates the EPC and a fixed of access systems consisting of the eUTRAN or UTRAN. EPS has been designed from the floor as much as support seamless mobility and QoS with minimum latency for IP services mobile mechanic largo.

EVOLVING ALL-IP FLAT ARCHITECTURE

The 3GPP is evolving wi-fi networks to end up flatter and greater simplified. In EPS’s consumer plane, as an instance, there are handiest styles of nodes (base stations and gateways), even as in modern hierarchical networks there are 4 sorts, which include a centralized RNC. Another simplification is the separation of the manage aircraft, with a separate mobility-control community element. It is worth noting that similar optimizations are enabled within the advanced HSPA network architecture, imparting a likewise flattened structure.

A key difference from cutting-edge networks is that the EPC is described to guide packet-switched visitors simplest. Interfaces are based totally on IP protocols. This means that every one services may be added through packet connections, along with voice. Thus, EPS provides savings for operators by using using a unmarried-packet network for all offerings.

EVOLVED NODE-B (eNB)

A great fact is that maximum of the everyday protocols applied in trendy RNC are moved to the eNB. The eNB, just like the Node B capability within the evolved HSPA structure, is also liable for header compression, ciphering and reliable delivery of packets. On the manipulate plane, features such as admission manipulate and radio useful resource management are also integrated into the eNB. Benefits of the RNC and Node B merger consist of reduced latency with fewer hops inside the media route, and distribution of the RNC processing load into multiple eNBs.

SERVING AND PDN GATEWAYS

Between the get entry to community and the PDNs (e.G., the Internet), gateways support the interfaces, the mobility wishes and the differentiation of QoS flows. EPS defines two logical gateway entities, the S-GW and the P-GW. The S-GW acts as a neighborhood mobility anchor, forwarding and receiving packets to and from the eNB wherein the UE is being served. The P-GW, in turn, interfaces with the outside PDNs, which includes the Internet and IMS. It is also answerable for numerous IP features, consisting of deal with allocation, policy enforcement, packet category and routing, and it offers mobility anchoring for non-3GPP get admission to networks. In practice, each gateways may be implemented as one physical network detail, depending on deployment scenarios and dealer support.

MOBILITY MANAGEMENT ENTITY (MME)

The MME is a signaling-handiest entity, therefore person IP packets do not undergo the MME. Its most important feature is to manipulate the UE’s mobility. In addition, the MME also performs authentication and authorization; idle-mode UE tracking and reachability; safety negotiations; and NAS signaling. An benefit of a separate network detail for signaling is that operators can develop signaling and visitors capability independently. A comparable benefit also can be achieved in HSPA Release 7’s direct-tunnel structure, wherein the SGSN turns into a signaling-simplest entity.

EFFICIENT QoS

An essential factor for any all-packet network is a mechanism to guarantee differentiation of packet flows based on its QoS requirements. Applications inclusive of video streaming, HTTP, or video telephony have special QoS desires, and need to get hold of differentiated service over the network. With EPS, QoS flows referred to as EPS bearers are installed among the UE and the P-GW. Each EPS bearer is associated with a QoS profile, and is composed of a radio bearer and a mobility tunnel. Thus, every QoS IP glide (e.G., VoIP) can be related to a special EPS bearer, and the network can prioritize packets therefore. The QoS method for packets getting back from the Internet is much like that of HSPA. When receiving an IP packet, the P-GW performs packet type based totally on parameters together with rules acquired from the PCRF, and sends it thru the proper mobility tunnel. Based at the mobility tunnel, the eNB can map packets to the perfect radio QoS bearer.

EPS SEAMLESS MOBILITY

Seamless mobility is without a doubt a key attention for wi-fi structures. Uninterrupted lively handoff across eNBs is the first situation one generally considers. However, different eventualities along with handoffs across center networks (i.E., P-GW, MME), switch of get admission to technology, and idle mobility are also important eventualities covered by EPS.

SEAMLESS ACTIVE HANDOFFS

EPS enables seamless energetic handoffs, supporting VoIP and other actual-time IP programs. Since there’s no RNC, an interface between eNBs is used to aid signaling for handoff education. In addition, the S-GW behaves as an anchor, switching mobility tunnels across eNBs. A serving eNB keeps the coupling between mobility tunnels and radio bearers, and additionally keeps the UE context1. As coaching for handoff, the supply eNB (eNB 1) sends the coupling statistics and the UE context to the goal eNB (eNB 2). This signaling is brought on through a radio size from the UE, indicating that eNB 2 has a better signal. Once eNB 2 alerts that it is prepared to carry out the handoff, eNB 1 commands the UE to trade the radio bearer to eNB 2. For the eNB handoff to complete, the S-GW have to update its facts with the brand new eNB this is serving the UE. For this section, MME coordinates the mobility-tunnel transfer from eNB 1 to eNB 2. MME triggers the replace on the S-GW, based totally on signaling received from eNB 2 indicating that the radio bearer was effectively transferred.

EFFICIENT IDLE MOBILITY

An additional mobility factor to recall with a new wi-fi core community is the mechanism to identify the approximate vicinity of the UE whilst it isn’t always lively. EPS affords an green solution for idle mobility management. The fundamental concept is to accomplice a cluster of eNBs into monitoring regions (TAs). The MME tracks which TA the UE is in, and if the UE actions to a distinct TA, the UE updates the MME with its new TA. When the EPS GW gets records for an idle UE, it will buffer the packets and query the MME for the UE’s vicinity. Then the MME will web page the UE in its most cutting-edge TA. EPS consists of a new idea, that is the capacity of a UE to be registered in more than one TAs concurrently. This permits the UE to minimize battery consumption for the duration of intervals of excessive mobility, since it does not want to continuously update its area with the MME. It additionally minimizes the registration load on TA barriers.

HETEROGENOUS NETWORK MOBILITY

LTE is expected as a supplement to current HSPA/HSPA+ networks in locations which have high call for for facts and improved broadband revel in. Therefore, LTE get right of entry to networks will co-exist with the giant coverage of HSPA/HSPA+ networks, consequently requiring sturdy mechanisms to interoperate. For facts interoperability, EPC will aid interfaces among the prevailing SGSNs and the MME and S-GW, for you to permit facts handoffs. For voice-carrier continuity, 3GPP is likewise running on standardizing a voice-name continuity technique so as to allow seamless operation among VoIP over LTE and circuit-switched voice over R99.

CONCLUSIONS

EPS affords operators with green and robust core community architecture to support all IP services for LTE, HSPA and non-3GPP access networks. Fundamentally, it’s far a flattened structure that enables simplified network design while nonetheless assisting seamless mobility and advanced QoS mechanisms. Many of the everyday RNC features are included into the eNB, and the EPS defines a manage plane with a separate network detail, the MME. QoS logical connections are installed between the UE and the EPS GW, offering differentiation of IP flows at some stage in the whole community, and assembly the necessities for low-latency packages. The principles and design are just like the developed HSPA structure, offering operators with a smooth migration direction for their 3GPP middle networks.

LTE Packet Core Systems – Mobility and QoS