LTE Packet Core Systems - Mobility and QoS 1

LTE Packet Core SystemsABSTRACT

Long-Term Evolution (LTE) enhances HSPA’s success with better height statistics quotes, lower latency, and a more suitable broadband revel in high-demand regions. This uses wider-spectrum bandwidths, OFDMA and SC-FDMA air interfaces, and superior antenna strategies. These techniques enable high spectral performance and wonderful user revels in various converged IP services. To take full advantage of that broadband, get admission to networks, and allow the co-existence of a couple of technologies via a green, all-in-packet architecture, 3GPP™ implemented a brand new middle community, the developed packet center (EPC). EPC is planned for 3GPP Release Nine and should use various get entries to networks, including LTE, HSPA/HSPA+, and non-3GPP networks. The evolved packet system (EPS) contains the EPC and a set of entry rights to structures, including the eUTRAN or UTRAN. EPS has been designed from the ground up to aid seamless mobility and QoS with minimal IP services latency.



The 3GPP is evolving wireless networks to become flatter and more simplified. In EPS consumer aircraft, for instance, there are the handiest varieties of nodes (base stations and gateways), while in contemporary hierarchical networks, there are four types, including a centralized RNC. Another simplification is separating the control plane with a separate mobility-management network element. It is worth noting that similar optimizations are enabled inside the developed HSPA community architecture, offering a flattened architecture.

A key distinction from current networks is that the EPC is described to guide packet-switched site visitors simplest. Interfaces are primarily based on IP protocols. This means that all services can be introduced via packet connections and voice. Thus, EPS gives savings for operators through the usage of an unmarried-packet community for all offerings.



A great fact is that most of the everyday protocols implemented in modern-day RNC are moved to the end. The eNB, much like the Node B functionality within the developed HSPA architecture, is also chargeable for header compression, ciphering, and reliable shipping of packets. On the managed aircraft, capabilities inclusive of admission management and radio-useful resource control are also incorporated. The RNC and Node B merger benefits consist of decreased latency with fewer hops within the media route and the RNC processing load distribution into a couple of eNBs.


Between the get entry to the network and the PDNs (e.g., the Internet), gateways assist the interfaces, the mobility core desires, and the differentiation of QoS flows. EPS defines logical gateway entities, the S-GW and the P-GW. The S-GW acts as a neighborhood mobility vans 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, including the Internet and IMS. It is likewise answerable for numerous IP capabilities, including the deal with allocation, policy enforcement, packet classification, and routing, and it affords mobility anchoring for non-3GPP to get admission to networks. Both gateways can be implemented as one bodily community detail in the exercise, depending on deployment scenarios and dealer help.


The MME is a signaling-best entity; hence consumer IP packets no longer undergo the MME. Its major feature is to manipulate the UE’s mobility. The MME also plays authentication and authorization, idle-mode UE monitoring and reachability, security negotiations, and NAS signaling. A gain of a separate community element for signaling is that operators can grow signaling and site visitors’ abilities independently. A similar advantage can also be executed in HSPA Release 7’s direct-tunnel architecture, wherein the SGSN will become the most effective signaling entity.



An important thing for any all-packet network is a mechanism to guarantee the packet flow differentiation primarily based on its QoS requirements. With video streaming, HTTP, or video telephony, applications have unique QoS desires and must acquire differentiated providers over the network. With EPS, QoS flows, called EPS bearers, are installed between the UE and the P-GW. Each EPS bearer is related to a QoS profile and consists of a radio bearer and a mobility van tunnel. Thus, each QoS IP float (e.g., VoIP) will be associated with a distinct EPS bearer, and the network can prioritize packets accordingly. The QoS system for packets arriving from the Internet is similar to that of HSPA. When receiving an IP packet, the P-GW plays packet category primarily based on parameters, including policies acquired from the PCRF and sends it through the proper mobility tunnel. The eNB can map packets to the ideal radio QoS bearer based on the mobility tunnel.


Seamless mobility is a key consideration for wi-fi systems. Uninterrupted lively handoff across eNBs is the primary scenario one commonly considers. However, situations such as handoffs across middle networks (i.e., P-GW, MME), transfer of getting admission to technologies, and idle mobility are also essential scenarios EPS includes.


EPS enables seamless lively handoffs, helping VoIP and other real-time IP applications. Since there is no RNC, an interface among eNBs is used to aid signaling for handoff coaching. Besides, the S-GW behaves as an anchor, switching mobility tunnels across eNBs. A serving maintains the coupling among mobility vans tunnels and radio bearers and maintains the UE context1. As practice for handoff, the supply B (B 1) sends the coupling statistics and the UE context to the target eNB (eNB 2). This signaling is triggered by a radio measurement from the UE, indicating that eNB 2 has a higher sign. Once eNB 2 signals that it is ready to carry out the handoff, eNB 1 instructions the UE to trade the radio bearer to and 2. For the eNB handoff to complete, the S-GW must replace its information with the brand new serving the UE. MME coordinates the mobility-tunnel switch from eNB 1 to 2 for this segment. MME triggers the S-GW replacement, primarily based on signaling received from eNB 2 indicating that the radio bearer turned into correctly transferred.


An extra mobility element to don’t forget with a brand new Wwi-fiF core network is the mechanism to pick out the UE’s approximate location while it is not energetic. EPS gives an efficient solution for idle mobility management. The basic idea is to companion a cluster of eNBs into monitoring areas (TAs). The MME tracks which TA the UE is in, and if the UE moves to a distinct TA, it updates the MME with its new TA. When the EPS GW gets statistics for an idle UE, it will buffer the packets and question the MME for the UE’s area. Then the MME will webpage the UE in its maximum cutting-edge TA. EPS consists of a new concept: the ability of a UE to be registered in more than one TAs simultaneously. This allows the UE to decrease battery consumption at some point in periods of high mobility vans because it does not need to constantly update its region with the MME. It also minimizes the registration load on TA barriers.


LTE is predicted to complement modern-day HSPA/HSPA+ networks in places with a high call for records and superior broadband revel. Therefore, LTE gets entry to networks that will co-exist with HSPA/HSPA+ networks’ giant insurance, thus requiring robust mechanisms to interoperate. For information interoperability, EPC will aid interfaces among the existing SGSNs and the MME and S-GW, which allows you to allow statistics handoffs. For voice-provider continuity, 3GPP is likewise working on standardizing a voice-name continuity approach, a good way to allow seamless operation between VoIP over LTE and circuit-switched voice over R99.


EPS provides operators with efficient and strong middle network architecture to assist all IP offerings for LTE, HSPA, and non-3GPP to get the right of entry to networks. Fundamentally, it is a flattened architecture that permits simplified network design while helping seamless mobility vans and superior QoS mechanisms. Many of the standard RNC functions are integrated into the end, and the EPS defines a control plane with a separate community element, the MME. QoS logical connections are set up among the UE and the EPS GW, offering differentiation of IP flows throughout the whole network and assembling the requirements for low-latency applications. The principles and design are like the evolved HSPA architecture, supplying operators with an easy migration path for their 3GPP core networks.