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Wireless Technologies for the Last-mile

WiFi

WiFi was originally designed as an alternative to Ethernet to wireless LAN functionality. The

IEEE802.11 standard, on which WiFi technology is based, has undergone many iterations over the

years and newer versions are capable of supporting high-speed wireless access. All versions of WiFi

operate in unlicensed spectrum bands. The following table captures the capabilities of various

versions of WiFi.

802.11 Version Frequency Band

(GHz)

Peak data Rate

(Mbps)

Indoor Range

(m)

Outdoor Range

(m)

a 5 54 35 120

b 2.4 11 38 140

g 2.4 54 38 140

n 2.4, 5 150 70 250

ac 5 160 TBC TBC

Source: Wikipedia 

Note: IEEE802.11ac standard is still in draft stage, so some details are yet to be finalised.

3G

The term 3G is used to refer to a number of wireless technologies. The UMTS system was

standardized by 3GPP in the late 90s and comes in several flavours such as WCDMA, HSPA and TD-

SCDMA (used in China only). The CDMA2000 system was standardized by 3GPP2 and later evolved to

the EV-DO technology. As per ITU, EDGE and WiMAX (version 1.0) are also 3G technologies. All of 

these have been designed for cellular systems, with coverage ranging from a few hundred metres to

several kilometres. All these technologies can operate on multiple frequency bands. A comparison of these

technologies is provided in the table below. 

Technology Channel Bandwidth Peak UL Data-

rate(Mbps)

Peak DL data-date

(Mbps)

EDGE 200 kHz 0.474 0.474

Evolved-EDGE 200 kHz 0.947 1.89

UMTS 5 MHz 0.384 0.384

HSPA 5 MHz 5.76 14.4

HSPA+ 5 MHz 11.5 42

EV-DO Rev. A 1.25 MHz 1.28 3.1

EV-DO Rev. B 5 MHz 4.9 14.7

WiMAX 1.0 20 MHz 56 128

Source: Rohde & Schwarz

The figures provided in the table above are for the specific channel bandwidth mentioned. HSPA, EV-DO and

WiMAX can use other channel bandwidths also, for which the corresponding data rates will be different.

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4G

LTE/LTE-Advanced and WiMAX 2.0 are considered as 4G wireless access technologies. While LTE

standard has been developed by 3GPP, WiMAX is based on the IEEE802.16m standard. Both these

are capable of supporting very high data rates and user mobility up to 500 km/h. These technologies

can provide coverage up to 100 km. These can operate over a large number of spectrum bands. Atthe same time, the channel bandwidth is also scalable (from 1.4 MHz to 100 MHz). Both

technologies support TDD and FDD modes of operation. The data rates of these technologies are

provided in the table below.

Technology Channel bandwidth

(MHz)

UL Data Rate

(Mbps)

DL Data Rate

(Mbps)

LTE 20 75 300

LTE-Advanced 100 500 1000

WiMAX 2.0 20 135 300

Source: Rohde & Schwarz

The figures provided in the table above are for the specific channel bandwidth mentioned. LTE and WiMAX can

use other channel bandwidths also, for which the corresponding data rates will be different.

All these technologies (WiFi, 3G and 4G) are being used globally for providing last-mile access. The particular

technology to be used depends on the deployment scenario, usage model, availability of spectrum etc.