5.1.4 Mobility and Radio Resource Management

Radio characteristics are measured by the UE and the eNode-B and reported to higher layers in the network. These include, e.g. measurements for intra- and inter-frequency handover, inter RAT handover, timing measurements and measurements for RRM.

Measurements for inter-RAT handover are defined in support of handover to GSM, UTRA FDD and UTRA TDD.

Measurements to be performed by a UE for mobility are classified in at least three measurement types:

• Intra-frequency E-UTRAN measurements;

• Inter-frequency E-UTRAN measurements;

• Inter-RAT measurements for UTRAN and GERAN.

In E-UTRAN RRC_CONNECTED state, network-controlled UE-assisted handovers are performed and various DRX cycles are supported.

E-UTRAN supports radio access network sharing based on support for multi-to-multi relationship between E-UTRAN nodes and EPC nodes (S1-flex).

Service-based redirection between GERAN / UTRAN and E-UTRAN is supported in both directions.

E-UTRAN mechanisms to support idle and active mode mobility between E-UTRAN and cdma2000 HRPD or 1XRTT.

5.1.5 Support for self configuration and optimization

Self-configuration process is defined as the process where newly deployed nodes are configured by automatic installation procedures to get the necessary basic configuration for system operation.

This process works in pre-operational state. Pre-operational state is understood as the state from when the eNB is powered up and has backbone connectivity until the RF transmitter is switched on.

Self-optimization process is defined as the process where UE & eNB measurements and performance measurements are used to auto-tune the network.

This process works in operational state. Operational state is understood as the state where the RF interface is additionally switched on.

5.1.6 System Architecture Evolution

SA2 started its own Study on System Architecture Evolution (SAE) whose objective was "to develop a framework for an evolution or migration of the 3GPP system to a higher-data-rate, lower-latency, packet-optimized system that supports, multiple RATs. The focus of this work is on the PS domain with the assumption that voice services are supported in this domain". It was initiated when it became clear that the future is IP with everything (the All-IP Network (AIPN) - see TR 22.978), and that access to the 3GPP network would ultimately be not only via UTRAN or GERAN but by WiFi, WiMAX, or even wired technologies.  Thus SAE has as its main objectives:

• Impact on overall architecture resulting from RAN's LTE work;

• Impact on overall architecture resulting from SA1's AIPN work;

• Overall architectural aspects resulting from the need to support mobility between heterogeneous access networks.

This figure from TR 23.882 shows the evolved system architecture, possibly relying on different access technologies:

* Colour coding:

red

indicates new functional element / interface

Logical high level architecture for the evolved system

New reference points have been defined:

S1: It provides access to Evolved RAN radio resources for the transport of user plane and control plane traffic. The S1 reference point shall enable MME and UPE separation and also deployments of a combined MME and UPE solution.

S2a: It provides the user plane with related control and mobility support between a trusted non 3GPP IP access and the SAE Anchor.

S2b: It provides the user plane with related control and mobility support between ePDG and the SAE Anchor.

S3: It enables user and bearer information exchange for inter 3GPP access system mobility in idle and/or active state. It is based on Gn reference point as defined between SGSNs. User data forwarding for inter 3GPP access system mobility in active state (FFS).

S4: It provides the user plane with related control and mobility support between GPRS Core and the 3GPP Anchor and is based on Gn reference point as defined between SGSN and GGSN.

S5a: It provides the user plane with related control and mobility support between MME/UPE and 3GPP anchor.

It is FFS whether a standardized S5a exists or whether MME/UPE and 3GPP anchor are combined into one entity.

S5b: It provides the user plane with related control and mobility support between 3GPP anchor and SAE anchor.  It is FFS whether a standardized S5b exists or whether 3GPP anchor and SAE anchor are combined into one entity.

S6: It enables transfer of subscription and authentication data for authenticating/authorizing user access to the evolved system (AAA interface).

S7: It provides transfer of (QoS) policy and charging rules from PCRF to Policy and Charging Enforcement Point (PCEP). The allocation of the PCEP is FFS.

SGi: It is the reference point between the Inter AS Anchor and the packet data network. Packet data network may be an operator external public or private packet data network or an intra operator packet data network, e.g. for provision of IMS services. This reference point corresponds to Gi and Wi functionalities and supports any 3GPP and non-3GPP access systems.

The interfaces between the SGSN in 2G/3G Core Network and the Evolved Packet Core (EPC) will be based on the GTP protocol. The interfaces between the SAE MME/UPE and the 2G/3G Core Network will be based on the GTP protocol.

5.2 LTE – Physical Layer (LTE-Phys) UID_330018

Resources: R1