Long-Term Evolution (LTE): The Basis for Wireless 4G Technology

bottlelewdΚινητά – Ασύρματες Τεχνολογίες

12 Δεκ 2013 (πριν από 5 χρόνια και 4 μήνες)

114 εμφανίσεις


Patrick Urgento

Sr Systems Engineer

What is LTE

Specification managed by 3GPP organization


Generation Partnership Project

Scope to create global 3G spec based on GSM architecture

UMTS (Universal Mobile Telephone System) Rel 99

HSPDA (High Speed Download Packet Access) Rel 5

HSPUA (Upload Access) Rel 6

HSPA+ Rel 7, enhancements in Rel 8

New LTE specification in Release 8, 4G Scope

What is 4G?


Generation of Mobile communications

First Gen Analog, AMPS

2G, Digital, IncreaseVoice Capacity


3G High Speed Data; EVDO, UMTS, HSPA

ITU defines 4G as 100 Mbps mobile, 1 Gbps stationary

Advanced & WiMax 2.0 4G certified, theoretically capable

Realistic? Nokia lab demo w/ 8 antennas, 60 MHz & 1 user

Market 4G defined as ~10X 3G or 5
10+ Mbps

Current gen WiMax, LTE & HSPA+

LTE Multiplexing

1G: FDMA 1 user, 1 channel, 30kHz, add channels for more users

2G: CDMA or TDMA, 200 kHz to 1.25 MHz

3G: CDMA & TDMA hybrid

1.25 to 5 MHz channels

1.2288 to 3.84

4G: LTE &


Slow down symbol rates, use multiple orthogonal frequencies

15kHz channels Orthogonally spaced. 15

802.11 A,G,N & HDTV all use OFDM

LTE Channel Sizes

2G; GSM= 200 kHz, 1xRTT = 1.25 MHz

3G; HSPA = 5 MHz, EVDO = 1.25 MH

Wasted spectrum

Guard bands between carriers or left

Leftover spectrum unused Holdings

LTE is Flexible Channel Size

1.4, 3, 5, 10, 15 or 20 Mhz

~100 subcarriers per MHz (128, 256, 512, 1024, 1536 or 2048)

Subcarriers are 15 kHz

LTE Releases

Release 8

Initial LTE release

Up to 4x4 MIMO

Release 9

Minor enhancements

Currently built out by VZ, ATT & S

Release 10, LTE Advanced

2013 Commercial Availability

Channel bonding up to 5X


Voice & LTE

LTE is a data focused technology, 3GPP never specified voice

Circuit Switched Fall Back

Use 2G/3G technology to carry Voice, 1xRTT,UMTS, HSPA

SVLTE, Simultaneous Voice and LTE, uses extra power

Currently deployed


Carrier controlled COS VoIP with IMS interconnection

Efficient Cellular codecs, IMS transcodes to SIP or PSTN

Widely agreed upon, most likely future

OTT (Over the Top), Skype, Vonage, etc

No Quality of Service, inefficient codecs


How fast is it? Depends?

Channel size, Carrier Bonding, MIMO

Network Load
> Pricing

Signal Strength more important than ever

What does it do for me?

“Greasy Fast Speed!!!”

Wireline performance, latency, throughput

More applications, More operational users

Better Video Communications (Surveillance, Training, Service)

Consolidate Voice, VoIP, SIP