LTE EARFCN

EARFCN stands for E-UTRA Absolute Radio Frequency Channel Number.In LTE, the carrier frequency in the uplink and downlink is designated by EARFCN, which ranges between 0-65535.

• EARFCN uniquely identify the LTE band and carrier frequency.
  For example Band-1 and Band-4 can have same Rx frequency 2110-2170 MHz,  but their EARFCN are different.
• EARFCN is independent of channel bandwidth.

LTE Frequency Bands

	Downlink			Uplink
Band	FDL_low (MHz)	NOffs-DL	NDL Range	FUL_low (MHz)	NOffs-UL	NUL Range
1	2110	0	0-599	1920	18000	18000-18599
2	1930	600	600-1199	1850	18600	18600-19199
3	1805	1200	1200-1949	1710	19200	19200-19949
4	2110	1950	1950-2399	1710	19950	19950-20399
5	869	2400	2400-2649	824	20400	20400-20649
6	875	2650	2650-2749	830	20650	20650-20749
7	2620	2750	2750-3449	2500	20750	20750-21449
8	925	3450	3450-3799	880	21450	21450-21799
9	1844.9	3800	3800-4149	1749.9	21800	21800-22149
10	2110	4150	4150-4749	1710	22150	22150-22749
11	1475.9	4750	4750-4949	1427.9	22750	22750-22949
12	729	5010	5010-5179	699	23010	23010-23179
13	746	5180	5180-5279	777	23180	23180-23279
14	758	5280	5280-5379	788	23280	23280-23379
…
17	734	5730	5730-5849	704	23730	23730-23849
18	860	5850	5850-5999	815	23850	23850-23999
19	875	6000	6000-6149	830	24000	24000-24149
20	791	6150	6150-6449	832	24150	24150-24449
21	1495.9	6450	6450-6599	1447.9	24450	24450-24599
22	3510	6600	6600-7399	3410	24600	24600-25399
23	2180	7500	7500-7699	2000	25500	25500-25699
24	1525	7700	7700-8039	1626.5	25700	25700-26039
25	1930	8040	8040-8689	1850	26040	26040-26689
26	859	8690	8690-9039	814	26690	26690-27039
27	852	9040	9040-9209	807	27040	27040-27209
28	758	9210	9210-9659	703	27210	27210-27659
292	717	9660	9660-9769	N/A		-
31	462.5	9870	9870-9919	452.5	27760	27760-27809
...						-
33	1900	36000	36000-36199	1900	36000	36000-36199
34	2010	36200	36200-36349	2010	36200	36200-36349
35	1850	36350	36350-36949	1850	36350	36350-36949
36	1930	36950	36950-37549	1930	36950	36950-37549
37	1910	37550	37550-37749	1910	37550	37550-37749
38	2570	37750	37750-38249	2570	37750	37750-38249
39	1880	38250	38250-38649	1880	38250	38250-38649
40	2300	38650	38650-39649	2300	38650	38650-39649
41	2496	39650	39650-41589	2496	39650	39650-41589
42	3400	41590	41590-43589	3400	41590	41590-43589
43	3600	43590	43590-45589	3600	43590	43590-45589
44	703	45590	45590-46589	703	45590	45590-46589

Ref: ETSI TS 136 521-1 V11.2.0 (2013-10)

Radio Interface Techniques FDMA,TDMA,CDMA and OFDMA

Radio Interface Techniques

In wireless cellular systems, mobiles have to share a common medium for transmission. There
are various categories of assignment, the main four include:
FDMA (Frequency Division Multiple Access),
TDMA (Time Division Multiple Access),
CDMA (Code Division Multiple Access)
OFDMA (Orthogonal Frequency Division Multiple Access).

Frequency Division Multiple Access
In order to accommodate various devices on the same wireless network, FDMA divides the
available spectrum into sub-bands or channels. The concept of FDMA is Using this technique a dedicated channel can be allocated to a user, whilst other users occupy other channels, i.e. requencies.

In a cellular system mobiles typically occupy multiple channels; one for the downlink and one
for the uplink. This does however make FDMA less efficient since most data applications are
downlink intensive.

FDMA channels also suffer since they cannot be close together due to the energy from one
transmission affecting the adjacent/neighboring channels. To combat this, additional guard
bands between channels are required, which also reduces the system’s spectral efficiency.

Time Division Multiple Access
In TDMA systems the channel bandwidth is shared in the time domain. It shows how each device is allocated a time on the channel, known as a “timeslot”. These are then grouped into a TDMA frame. The number of timeslots in a TDMA frame is dependent on the system, for example GSM utilizes
8 timeslots.

Devices must be allocated a timeslot; therefore it is usual to have one or more timeslots
reserved for common control and system access.TDMA systems are normally digital and therefore offer additional features such as ciphering and integrity. In addition, they can employ enhanced error detection and correction schemes including FEC (Forward Error Correction). This enables the system to be more resilient to noise and interference and therefore they have a greater spectral efficiency when compared to FDMA systems.

Code Division Multiple Access
The concept of CDMA is slightly different to that of FDMA and TDMA. Instead of sharing
resources in the time or frequency domain, the devices are able to use the system at the same
time and using the same frequency/bandwidth. This is possible due to the fact that each
transmission is separated using a unique code.

There are two main types of CDMA, FHSS (Frequency Hopping Spread Spectrum) and DSSS
(Direct Sequence Spread Spectrum), with all the current cellular systems utilizing DSSS.

The basic concept of CDMA. The narrowband signals are spread with a wideband code and then transmitted. The receivers are designed to extract the encoded signal (with the correct code) and reject everything else as noise.

UMTS, cdmaOne and CDMA2000 all use CDMA. However the implementation of the codes
and the bandwidths used is different. For example UMTS utilizes a 5MHz channel bandwidth,
whereas cdmaOne uses only 1.25MHz.

Orthogonal Frequency Division Multiple Access
OFDMA (Orthogonal Frequency Division Multiple Access) is the latest addition to cellular
systems. It provides a multiple access technique based on OFDM (Orthogonal Frequency
Division Multiplexing).

It can be seen that the bandwidth is broken down to smaller units known as “subcarriers”. These are grouped together and allocated as a resource to a device. It can also be seen that a device can be allocated different resources in both the time and frequency domain.