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
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