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

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12 Δεκ 2013 (πριν από 3 χρόνια και 10 μήνες)

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LTE


Patrick Urgento

Sr Systems Engineer

What is LTE


Specification managed by 3GPP organization


3
rd

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
-
10


New LTE specification in Release 8, 4G Scope

What is 4G?


4
th

Generation of Mobile communications


First Gen Analog, AMPS


2G, Digital, IncreaseVoice Capacity
-

TDMA, GSM & 1xRTT


3G High Speed Data; EVDO, UMTS, HSPA


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


LTE
-
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
MSps


4G: LTE &
WiMax

= OFDM


Slow down symbol rates, use multiple orthogonal frequencies


15kHz channels Orthogonally spaced. 15
kSps


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


8x8 MIMO, SON

Voice & LTE


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


CSFB
-
Circuit Switched Fall Back


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


SVLTE, Simultaneous Voice and LTE, uses extra power


Currently deployed


VoLTE
-

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



WIIFM?


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