4G LTE uses technologies like OFDMA, SC-FDMA and MIMO to provide peak download rates of 100 Mbps and upload rates of 50 Mbps, with low latency. It employs an all-IP packet switched network with scalable channel bandwidth between 5-20 MHz. The LTE network architecture consists solely of evolved NodeBs which simplify the design.

1. 4G LTE
Team 9

2. 4G Standards
 International Mobile
Telecommunications –
Advances (IMT-A) set
by the International
Telecommunications
Union – Radio (ITU-R)
 All IP packet switch
network
 1Gbit/s stationary,
100Mbit/s moving
 Scalable channel
bandwidth 5-20 MHz

3. LTE Technologies / Features
 E-UTRA – LTE’s air interface
 Transfer capabilities
 DL and UL schemes
 Protocol Architecture
 Spectrum Flexibility
 Cell size support
 Network architecture

4. Data Rate
 Peak download rate of 100 Mbit/s
 Peak upload rate of 50 Mbit/s
 Low handoff and data transfer latencies (sub
5-ms for small IP packets)
How is this achieved?

5. OFDM
OFDM
Single Carrier
• Serial Symbols
S1 • Wide Frequency
S2 • Short Symbol Time
S1
S2
S3
S5
S4
Time S3 Time
S4
S5
• Parallel Symbols
Frequency
• Narrow FrequencyFrequency
• Long Symbol Time

6. Downstream Modulation
 OFDMA (Orthogonal frequency-division multiple
access)
 Multi-user version of OFDM
 Achieved by assigning subsets of subcarriers to
individual users
 Allows simultaneous low-data rate transmission
 High power cost
Sub-Carriers
Sub-Carriers
S1
S2
S3
S5
S4
Frequency Time

7. Upstream Modulation
 SC-FDMA (Single carrier frequency - division
multiple access)
 Lower peak-to-average-power (PAPR)
 Acceptable performance loss

8. MIMO – Multiple Input Multiple
Output
S1
DSP Tx Rx DSP
S2

9. E-UTRA Protocol Stack
 MAC: HARQ error correction;
dynamic scheduling between
UEs
 RLC: ARQ error correction;
data formatting
 PDCP: ciphering; error
correction during handoff
 RRC: handles broadcast
information, security keying
 NAS: security control;
authentication

10. Spectrum Flexibility
 Allows for cell
bandwidth:
 1.4 MHz
 3 MHz
 5 MHz
 10 MHz
 20 MHz
 Cell sizes can range
from 1-100 km

11. E-UTRA Network Architecture
 Network consists of
only evolved-NodeBs
 eNodeBs consist of
individual radio
network controllers,
simplifying the
network architecture

12. LTE vs 4G Standards
 All IP packet switch network
 1Gbit/s stationary, 100Mbit/s
moving
 Scalable channel bandwidth 5-20
MHz

13. FUTURE: LTE – Advanced
Circuit + Packet Packet
Switching Switching

14. Questions
?