The EPC is a multi-access core network based on the Internet Protocol (IP) which allows operators to deploy and operate one common packet core network for 3GPP radio accesses (LTE, 3G, and 2G), Non 3GPP radio accesses (e.g., HRPD, WLAN, and WIMAX), and fixed accesses (e.g., Ethernet, DSL, and Cable). The EPC supports optimized handover schemes providing terminals with seamless connectivity between different radio accesses (e.g., between LTE and HRPD). Standardized roaming interfaces enable operators to offer their subscribers global access across a range of different access technologies. The network-controlled and class-based QoS concept of the EPC has been aligned with 3GPP's Policy and Charging Control (PCC) framework. This maximizes operator control over all PCC/QoS functions that are distributed across different network nodes including the terminal.

The LTE radio access is based on Orthogonal Frequency Division Multiplexing (OFDM) and supports different carrier bandwidths (1.25 - 20 MHz -) in both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes. This provides great flexibility for operators to use existing and future radio spectrum allocations. The LTE radio access is based on shared channel access providing peak data rates of 75 Mb/s in uplink direction and 300 Mb/s in downlink direction. Improved coverage and battery lifetime have been important goals in the development of the LTE specifications. Unlike the 2G/3G, 3GPP radio access networks, which are also connected to the circuit-switched domain of the 3GPP core network, the LTE-RAN is only connected to the EPC. The LTE-RAN protocols and user plane functions have therefore been optimized for the transmission of traffic from IP-based real time and non real time applications/services.

Scope of Contributions
This feature topic of the Applications & Practice Series is intended to provide tutorial information and overview articles to the Communications Magazine readers on 3GPP SAE/LTE Release 8. Topics of interest include (but are not limited to):

• Support of a variety of different access systems (existing and future), mobility and service continuity between these access systems, and access selection based on combinations of operator policies, user preferences and access network conditions;
• How to realize improvements in basic system performance e.g. communication delay, communication quality, connection set-up time etc...?
• How to maintain the negotiated QoS across the whole system; in particular to address include inter-domain and inter-network interworking?
• Identify the capability expansion required taking into account migration and co-existence with the existing system
• Performance analysis and benchmarking
• Whether there is a need for a modified network architecture and/or different functional split between network nodes (compared to the current 3GPP architecture);
• How to provide a very low latency (including C-plane) for the overall network (including core network, radio access network and radio access technology)?
• How to provide the efficient support of the various types of services, especially from the PS domain(e.g. Voice over IP, Presence)?
• Service aspects to be investigated (non-exhaustive list): Network resiliency, redundancy and reliability
• For radio interface physical layer, the feature includes:
  • Physical channels and mapping of transport channels
  • Channel coding and physical channel mapping
  • MIMO and transmit diversity
  • MBMS functionality in physical layer
  • Physical layer procedures
  • Physical layer measurements
  • UE physical layer capabilities
• For radio interface layer 2 and 3:
  • Radio interface protocol architectures
  • MAC, RLC, PDCP and RRC protocols
  • Mobility solution based on hard handovers with downlink data forwarding between base stations
  • UE capabilities
• For Radio Network interfaces:
  • Control plane protocols
  • User plane protocols
• For radio transmission and reception:
  • UE radio transmission and reception
  • Base Station radio transmission and reception
  • Base Station and UE conformance testing
  • Requirements for support of Radio Resource Management
  • Selection of necessary combinations of bandwidth and frequency band to be standardised and the priority of the work.
• Supporting technologies for realization
  • Base station upgrades
  • RF considerations for MIMO technologies
  • Integrated chip-set solutions for handsets supporting multiple RAT
  • Multimode considerations for software architecture
  • Integration of RAT technologies and applications (multimedia. Graphics, etc)
  • Reconfigurable platforms and hardware/software partitioning
  • Initial performance measurements and field test results

Submission
Articles should be tutorial in nature and should be written in a style comprehensible to readers outside the specialty of the field. All submissions will be reviewed based on technical merit, relevance and readability. Articles should have no more than 4,500 words, no more than 6 tables/figures, and no more than 15 references. Authors must follow the IEEE Communications Magazine's guidelines for preparation of the manuscript. Complete guidelines for prospective authors can be found at www.comsoc.org/pubs/commag/sub_guidelines.html. All articles to be considered for publication must be submitted through IEEE Manuscript Central (http://commag-ieee.manuscriptcentral.com). Select "Next Generation 3GPP Technologies" from the drop down menu in order to have your manuscript submitted to this feature topic.

Guest Editors

Kalyani Bogineni
Verizon
kalyani.bogineni@verizon.com

Reiner Ludwig
Ericsson
reiner.ludwig@ericsson.com

Preben Mogensen
Nokia Siemens Networks
preben.mogensen@nsn.com

Vish Nandlall
Nortel Networks
vnandlal@nortel.com

Vojislav Vucetic
Cisco Systems
vvucetic@cisco.com

Byung K. Yi
LG Electronics
byungkyi@lge.com

Zoran Zvonar
MediaTek Wireless
zoran.zvonar@mediatek.com