What is 4G/LTE ?
The 3GPP Long Term Evolution (LTE) represents a major advance in cellular technology. LTE is designed to meet carrier needs for high-speed data and media transport as well as high-capacity voice support well into the next decade. It will enable operators to offer high performance, mass-market mobile broadband services, through a combination of high bit-rates and system throughput - in both the uplink and downlink - with low latency.
LTE offers scalable bandwidths, from less than 5MHz up to 20MHz, together with support for both FDD paired and TDD unpaired spectrum. The LTE-SAE architecture reduces the number of nodes, supports flexible network configurations and provides a high level of service availability. Furthermore, LTE-SAE will interoperate with GSM, WCDMA/HSPA, TD-SCDMA and CDMA.
LTE supports LTE-FDD and LTE-TDD
<p>FDD-LTE (Frequency Division Duplexing LTE) and TDD-LTE (Time Division Duplexing LTE). The LTE network architecture, protocol stack, radio management, and MAC layers are identical, and there are only minor differences in about 15 percent of the physical layer 1. All of the key features of LTE and LTE¬Advanced are identical for both FDD and TDD.</p>
Frequency band LTE-FDD
>Frequency Band from Band 1 to Band 29 allocated to LTE -FDD from 700/800Mhz1800 Mhz,1900Mhz, 2100Mhz,2300Mhz and 3400 Mhz
Frequency Band LTE-TDD
Frequency Band from Band 33 to Band 44 allocated to LTE -TDD from 1900 Mhz to 3800Mhz and a New Band 44 703-803Mhz
LTE MAIN TECHNOLOGIES
OFDM (Orthogonal Frequency Division Multiplex):
MIMO (Multiple Input Multiple Output
SAE (System Architecture Evolution):
Key Features of LTE
1. Multiple access scheme
Uplink: Single Carrier FDMA (SC-FDMA)
2. Adaptive modulation and coding
DL modulations: QPSK, 16QAM, and 64QAM
UL modulations: QPSK and 16QAM
Rel-6 Turbo code: Coding rate of 1/3, two 8-state constituent encoders, and a contention
free internal interleaver.
3. Bandwidth scalability for efficient operation in differently sized allocated spectrum bands
4. Possible support for operating as single frequency network (SFN) to support MBMS
5. Multiple Antenna (MIMO) technology for enhanced data rate and performance.
6. ARQ within RLC sublayer and Hybrid ARQ within MAC sublayer.
7.Power control and link adaptation
8. Implicit support for interference coordination
9. Support for both FDD and TDD
10.Channel dependent scheduling & link adaptation for enhanced performance.
11.Reduced radio-access-network nodes to reduce cost,protocol-related pro/ cessing time & call set-up time
System Architecture Evolution (SAE)
System Architecture Evolution (SAE) is the core network architecture of 3GPP’s future LTE
wireless communication standard.SAE is the evolution of the GPRS Core Network, with some differences.
The main principles and objectives of the LTE-SAE architecture include :
A common anchor point and gateway (GW) node for all access technologies
IP-based protocols on all interfaces;
Simplified network architecture
All IP network
All services are via Packet Switched domain
Support mobility between heterogeneous RATs, including legacy systems as GPRS, but also non-3GPP systems (say WiMAX)
Support for multiple, heterogeneous RATs, including legacy systems as GPRS, but also non-3GPP systems (say WiMAX)
what is 4g long term evolution ?