-: Wireless WAN Connections. 2 2
In this lesson, we're going to talk about 3 3
wireless wide area network connections. 4 4
Now, wireless WAN connections is an area 5 5
where there are several different options to consider, 6 6
including cellular, microwave, 7 7
satellite and high-frequency radio. 8 8
For this reason, this is going to be a longer lesson. 9 9
Now, first let's talk about cellular 10 10
because most of us have a smartphone in our pocket 11 11
and we use cellular everyday 12 12
to connect to the wide area network known as the internet. 13 13
Now, when we talk about cellular, 14 14
this includes not just our smartphones though 15 15
but also our tablets, 16 16
dedicated cellular modems for corporate networks 17 17
or cellular wireless access points known as hotspots. 18 18
There is a wide range of cellular technologies in use, 19 19
including 2G, 3G, 4G, LTE, and 5G. 20 20
When you hear someone talking about a G, like 4G or 5G, 21 21
they're basically talking about which generation 22 22
of cellular technology is being used by a cellular modem 23 23
in that smartphone or other device. 24 24
Basically, for any of these devices 25 25
to connect to a cellular network, 26 26
they have to have an embedded cellular modem 27 27
that supports one or more of these different technologies 28 28
and the associated frequencies for them. 29 29
Now, the very first cellular networks we had, 30 30
which we now call 1G, 31 31
were developed all the way back in the 1980s. 32 32
These 1G phones communicated using a frequency of 30 KHz 33 33
and had a bandwidth of about 2 Kbps or 2,000 bps, 34 34
so we really weren't pushing 35 35
a lot of data over these 1G handsets. 36 36
Instead, they were dedicated to providing voice calls 37 37
for the most part. 38 38
As time went on, 39 39
cellphones moved into their second generation known as 2G 40 40
during the late 1990s. 41 41
2G devices communicate over a GSM network 42 42
using the 1,800 MHz frequency band. 43 43
The big difference here is that 2G devices 44 44
ran over a digital network that use multiplexing 45 45
and therefore, it was able to start using data 46 46
in addition to just providing phone calls. 47 47
Now, the data here wasn't super fast. 48 48
Here in 2G, 49 49
we're talking about speeds similar to a dial-up modem, 50 50
usually in the range of 14.4 Kbps to 64 Kbps using GPRS, 51 51
usually in the range of 14.4 Kbps to 64 Kbps using GPRS, 52 52
which is the general packet radio service. 53 53
In fact, when I started my very first company back in 1999, 54 54
I had a 2G Motorola flip phone that I used 55 55
and I was able to tether my laptop to that phone 56 56
and dial-up to connect to the internet. 57 57
And that way, I could email invoices to my clients 58 58
once I left their office using this low speed connection. 59 59
Now, 2G gave us a lot of benefits for cellular devices, 60 60
even though the speeds here for data were rather limited. 61 61
2G devices were the first to have SMS and text messaging 62 62
as well as the ability to do international roaming, 63 63
conference calling, 64 64
the use of the internet while away from our computers, 65 65
and other things like this. 66 66
The next evolution we had in 2G 67 67
was the introduction of EDGE, 68 68
or the Enhanced Data rates for GSM Evolution. 69 69
This brought our speeds up to about 1 Mbps 70 70
for most modern 2G devices, 71 71
like the very first iPhone that was released in 2008. 72 72
The third generation of cellulars saw the release of 3G 73 73
with faster data speeds. 74 74
At a minimum, 75 75
3G networks must support 144 Kbps to be called 3G 76 76
but most devices were faster than that 77 77
and they supported speeds around 384 Kbps 78 78
if you're moving in a car, 79 79
or up to 2 Mbps if you're walking or standing still. 80 80
To provide these faster speeds, 81 81
3G devices used a wider frequency band 82 82
with frequencies ranging 83 83
from 1.6 GHz all the way up to 2 GHz 84 84
within the 3G spectrum, 85 85
depending on where you lived in the world. 86 86
When it comes to 3G, 87 87
there are three different technologies that you might find: 88 88
WCDMA, HSPA, and HSPA+. 89 89
WCDMA is the Wideband Code Division Multiple Access, 90 90
which uses the UMTS standard 91 91
and could reach data speeds up to about 2 Mbps. 92 92
This is the slowest of the 3G technologies. 93 93
As an improvement to WCDMA, 94 94
there was HSPA or the High Speed Packet Access standard. 95 95
This could reach speeds of up to 14.4 Mbps. 96 96
This is sometimes referred to as 3.5G by the industry. 97 97
Then, over time, that wasn't fast enough, 98 98
so we went to HSPA+, High Speed Packet Access Evolution. 99 99
This brings us speeds up to about 50 Mbps 100 100
and is often referred to as 3.75G. 101 101
Now, after that, we got to our fourth generation 102 102
and this gave us 4G with even faster speeds 103 103
and the introduction of using MIMO, 104 104
which is multiple input, multiple output technology. 105 105
With 4G, we could get speeds of up to 100 Mbps while driving 106 106
or up to 1 Gbps 107 107
for fixed stationary cellular modems with a large antenna. 108 108
4G devices even used a wider frequency band than the others 109 109
covering frequencies from 2 to 8 GHz, 110 110
depending on the implementation in a given country. 111 111
Now, when 4G first came out, 112 112
it was often called 4G LTE or 4G Long Term Evolution. 113 113
These devices could reach speeds up to about 100 Mbps. 114 114
Now, over time, there was an improved version of LTE 115 115
known as LTE-A or LTE Advanced. 116 116
This is an advanced version of LTE 117 117
that add even more capabilities 118 118
and increase speeds of two to three times 119 119
of that of regular LTE and under perfect conditions 120 120
with a stationary cellular modem, 121 121
it could get up to speeds of 1 Gbps. 122 122
Our fifth generation of cellular is called 5G. 123 123
And again, it has faster speeds and more capabilities. 124 124
5G is actually relatively new 125 125
and it just began deployment back in 2019. 126 126
5G devices bring an enormous improvement 127 127
over previous generation's devices. 128 128
With 5G, it's possible to reach speeds up to 10 Gbps 129 129
using high-band 5G frequencies. 130 130
Now, this is one of the biggest differences with 5G 131 131
over the older generations. 132 132
With 5G, we actually split it up 133 133
into three different frequency bands. 134 134
There's low-band, mid-band and high-band frequencies. 135 135
Now, low-band frequencies are between 600 and 850 MHz 136 136
and they provide us with speeds of 30 to 250 Mbps. 137 137
The benefits of using this low-band frequency range 138 138
is it has a longer range 139 139
and can cover an area similar in size 140 140
to the older 4G networks. 141 141
The mid-band frequencies operate between 2.5 and 3.7 GHz. 142 142
This higher frequency band 143 143
is going to support higher data rates of 100 to 900 Mbps 144 144
but each cellular tower now 145 145
covers less area than the low-band or 4G towers could. 146 146
As of 2021, most 5G deployments are actually being done 147 147
using this mid-frequency towers 148 148
because it provides a good balance of coverage 149 149
with those higher speeds. 150 150
Now, the third frequency range we have 151 151
is known as the high-band frequencies 152 152
and these operate between 25 and 39 GHz. 153 153
This much higher frequency band 154 154
is going to support extremely high speeds in the Gbps range. 155 155
Now, the challenge here is that these frequencies operate 156 156
in the millimeter wave band 157 157
and this causes the range of these towers 158 158
to be much, much smaller. 159 159
Also, because of this smaller millimeter wave band, 160 160
the signal is easily blocked by walls, windows, 161 161
and other objects. 162 162
For this reason, there is not a lot of high-band deployments 163 163
going on quite yet. 164 164
So far, we're seeing these deployed 165 165
near areas where there's a lot of people expected to be 166 166
in one small area, such as a sports stadium, 167 167
an amusement park or convention centers. 168 168
All right, I just gave you a lot of facts 169 169
and figures about cellular 170 170
and all of the different generations of cellular technology, 171 171
and you're probably wondering, 172 172
do you need to memorize the speeds and frequencies 173 173
for each and every one? 174 174
And the answer is no, you don't. 175 175
Instead, you need to know that the higher the G, 176 176
such as 4G is higher 3G, 177 177
this would mean that the newer standard 178 178
and it has increased speeds. 179 179
It also is important to remember that 5G 180 180
comes in three different bands: 181 181
low-band, mid-band, and high-band. 182 182
As you go upward in the bands, you get faster speeds 183 183
but you decrease your coverage area. 184 184
For this reason, most 5G deployments 185 185
are going to use that mid-band frequency I spoke about, 186 186
leading to better coverage and pretty high speeds. 187 187
Now, in terms of cellular technologies, 188 188
they're going to operate 189 189
on one of two different underlying technologies, 190 190
either GSM or CDMA. 191 191
Which of these you're going to use 192 192
is really going to be determined 193 193
based on which area of the world you live in 194 194
and which cellular provider you're using 195 195
in your particular area. 196 196
For example, in the United States 197 197
if you're using T-Mobile or AT&T, these rely on GSM. 198 198
If you're using Verizon, they're going to normally use CDMA. 199 199
Now, if you live outside of the United States, 200 200
you're going to be using CDMA 201 201
if you live in Japan or South Korea. 202 202
If you live anywhere else in the world, 203 203
you're most likely going to be using GSM. 204 204
So, what exactly does GSM and CDMA mean? 205 205
Well, GSM is the Global System for Mobile Communications 206 206
and it is a cellular technology 207 207
that takes your voice during a call 208 208
and converts it into digital data. 209 209
Then, your device is given a channel and a time slot, 210 210
so that your service provider can combine your call 211 211
with several other calls 212 212
to maximize the efficiency of their network. 213 213
So, let's pretend they need to provide service 214 214
to four users simultaneously. 215 215
They could give each user a quarter of a second 216 216
to transmit their digital data, 217 217
then when it reaches the other side, 218 218
it could be combined back together 219 219
and converted into the analog voice, 220 220
so the person on the other end can hear what you're saying. 221 221
This is a form of time division 222 222
that was in the original GSM 2G standard 223 223
but it was modified using different code division methods 224 224
once 3G networks were rolled out 225 225
and then 4G and 5G within GSM. 226 226
Now, CDMA on the other hand, 227 227
is Code-Division Multiple Access. 228 228
It's a cellular technology that uses well, code division, 229 229
and it splits up that channel using code division. 230 230
So, instead of using time, 231 231
we're using some sort of encryption 232 232
or some sort of an algorithm. 233 233
For every call that's made, 234 234
the data's going to be encoded with a unique key 235 235
and then that data stream can be transmitted 236 236
over the same channel as all the other data streams. 237 237
On the other side, 238 238
the receiver then pulls it out based on that unique key 239 239
for each of those calls, devise those out, 240 240
and then makes them back into the analog call, 241 241
so the person can understand what you're saying. 242 242
Now, CDMA is actually a more powerful 243 243
and flexible technology than GSM. 244 244
In fact, when 3G GSM came out, 245 245
it actually adopted parts of CDMA 246 246
and termed it WCDMA, Wideband CDMA, 247 247
or the UMTS, Universal Mobile Telephone System. 248 248
So, which is better, CDMA or GSM, 249 249
and which one should get used? 250 250
Well, before 3G, 4G and 5G networks, 251 251
there really was a big difference 252 252
between these two technologies 253 253
but ever since 3G was introduced, 254 254
they're pretty much the same 255 255
and all using some form of CDMA, 256 256
even if you're buying a GSM phone 257 257
because they're using WCDMA or one of the evolutions of it. 258 258
The only reason we're really bringing up the idea 259 259
of CDMA vs GSM is so that you can realize 260 260
there is a difference in support 261 261
based on where you live in the world. 262 262
As I said, GSM is by far much more widely supported 263 263
across the globe. 264 264
So, if you or your business travels a lot, 265 265
you may want to carry a GSM supported smartphone 266 266
or hotspot with you. 267 267
Remember, it's important for you 268 268
to check with your cellular provider for hotspot options 269 269
in the areas you plan to work out of 270 270
before you head out there 271 271
to make sure what you have is compatible. 272 272
Most modern smartphones can also act as a hotspot for you, 273 273
using either tethering 274 274
or internet connection sharing over WiFi 275 275
but you can also purchase a dedicated hotspot device, 276 276
like this T-Mobile 4G LTE cellular modem I have 277 277
that has a wireless access point combined into it 278 278
in this single small form factor device 279 279
that I can carry with me 280 280
when I'm traveling around the world. 281 281
Now, the other major difference here 282 282
is that with a GSM phone, 283 283
you have a SIM card to identify yourself to the network, 284 284
whereas with a traditional CDMA phone, 285 285
you don't because CDMA devices are configured 286 286
and locked to a certain side of the provider. 287 287
For this reason, a lot of people prefer GSM phones, 288 288
since you can simply pull out your SIM card 289 289
and put a new one in when you're traveling 290 290
and have a new local service plan that's much cheaper 291 291
to be able to access data on your phones. 292 292
These days, though, 293 293
all modern phones support electronic SIMs too. 294 294
So, you can simply download an app from the app store 295 295
and change your SIM electronically to a local provider 296 296
to get data service once you get off the airplane, 297 297
instead of paying a large international roaming fee 298 298
to your cellular provider back in the States. 299 299
All right, our next wireless technology we need to discuss 300 300
is known as microwave 301 301
but not the kind you reheat your frozen burrito with. 302 302
Now, a microwave link is a communication system 303 303
that uses a beam of radio waves 304 304
in the microwave frequency range 305 305
to transmit information between two fixed locations. 306 306
When we're talking about the microwave frequency range, 307 307
we're talking about frequencies 308 308
in the range of 300 MHz to 300 GHz, 309 309
which includes UHF - ultra high frequency; 310 310
SHF - super high frequency; 311 311
and EHF - extremely high frequency. 312 312
Now, there's a lot of places that use microwave 313 313
for their connections. 314 314
It's actually quite popular for large college campuses 315 315
to be able to connect different portions of their network 316 316
over microwave antennas 317 317
located at the top of their buildings, 318 318
instead of having to run fiber 319 319
between all those different buildings. 320 320
Now, small businesses can also use microwave technology. 321 321
In fact, the main internet connection 322 322
that I have in my office in Puerto Rico is a microwave link. 323 323
I have an antenna on the roof of our building 324 324
and that connects to an antenna on the roof of the hospital 325 325
in the center of our city. 326 326
Now, once the connection reaches the antenna 327 327
at the top of the hospital, 328 328
it's combined with all the other businesses around our city 329 329
that have a similar setup. 330 330
And then, all of that is sent across the island 331 331
to our internet service provider 332 332
using a fiber connection they have from the hospital 333 333
back to our ISP. 334 334
Using this microwave link, 335 335
we can have speeds up to 1 Gbps to our offices, 336 336
depending on how much we want to pay per month 337 337
to our internet service provider. 338 338
As you can see, microwave technology 339 339
can provide you with a super fast point to point connection 340 340
between two places but there is a limitation. 341 341
Both antennas must maintain what is known as line of sight. 342 342
You see, the two antennas that make up this connection 343 343
have to be able to actually see each other. 344 344
Due to the visual horizon and the curvature of the earth, 345 345
this is normally going to create a distance limitation 346 346
of about 40 miles or 64 kilometers. 347 347
This is one of the reasons why our internet service provider 348 348
has actually leased the rooftop of the hospital in our town 349 349
to place the receiving antennas. 350 350
This is because I can't see from my house 351 351
all the way back to the ISP, 120 miles across the island. 352 352
So, I connect up to the hospital 353 353
and then they pass it over a fiber line over to the ISP. 354 354
This is because we're in a pretty hilly area. 355 355
And so, the hospital 356 356
is one of the tallest buildings in our city. 357 357
And so, most of the buildings and most of the offices 358 358
can get a direct line of sight from them 359 359
to the hospital's roof 360 360
if they're within 20 or 30 miles of the hospital. 361 361
Therefore, this became an ideal place 362 362
to install those antennas. 363 363
This allows the internet service provider 364 364
to pay for one fiber connection to that hospital 365 365
and then connect all of the microwave customers 366 366
to that high-speed fiber, 367 367
instead of having to run fiber directly to everybody's house 368 368
or everybody's office. 369 369
Now, when microwave connections 370 370
were first being sold to consumers, 371 371
it started being marketed under the term WiMAX, 372 372
instead of WiFi. 373 373
Now, WiMAX is really IEEE 802.16 374 374
when you're dealing with microwave access, 375 375
instead of the 802.11 standard that's used by WiFi. 376 376
WiMAX is an abbreviation 377 377
for Worldwide Interoperability for Microwave Access. 378 378
Microwave is actually a really good alternative 379 379
for cellular or DSL service 380 380
because it provides faster speeds 381 381
but it is usually going to cost you more 382 382
than just getting a cable modem 383 383
from your local internet service provider. 384 384
Also, microwave access does require an antenna 385 385
to be installed on the roof of your home or office 386 386
and that requires a professional to get up there 387 387
and install it for you. 388 388
Microwave connections are considered 389 389
a wireless fixed location service 390 390
because you're going to have a larger antenna 391 391
and a larger radio to pick up that signal properly 392 392
but it does provide you 393 393
with some really, really nice speeds. 394 394
Now, here you can see how WiMAX 395 395
compares to traditional cellular speeds 396 396
like GSM - which is 2G; UMTS - which is 3G; 397 397
HSPA - which is 3.5G; and WiMAX is faster than all of these. 398 398
But since the addition 399 399
of 4G and 5G mid-band cellular modems, 400 400
WiMAX tends to be in that same speed range, 401 401
while the cellular modems are much easier to install 402 402
because they don't require the mounting 403 403
of special antennas on your roof. 404 404
For this reason, WiMAX and microwave 405 405
is beginning to lose some popularity 406 406
as a direct-to-consumer internet service 407 407
but it is still often used for internal WAN connections, 408 408
such as in a business park or a college campus 409 409
if you can't run fiber between the buildings easily. 410 410
The next wireless connection we need to discuss 411 411
is satellite connections. 412 412
Satellite internet access 413 413
is a method of using communication satellites 414 414
located in space to connect a user to the internet. 415 415
Now, up until recently, 416 416
satellite internet was really reserved 417 417
for just a few special use cases. 418 418
For example, if you happen to live out in the countryside 419 419
or in a remote area where you couldn't get cable, 420 420
or cellular, or fiber, or copper connections, well, 421 421
you might want to look at using satellite internet. 422 422
Now, the great thing about satellite connectivity 423 423
is that you can get it anywhere 424 424
because pretty much the entire earth 425 425
can be covered by satellite internet at this point. 426 426
As long as you can mount an antenna 427 427
and has a clear line of sight 428 428
up to the satellite overhead in space, 429 429
you can get internet service. 430 430
For home users who live in a remote area 431 431
in the United States, for example, 432 432
you can use a commercial service like HughesNet, 433 433
which puts a small satellite dish on your roof, 434 434
much like DirecTV 435 435
or dish network does for your satellite TV 436 436
and then you can use that 437 437
to get some decently high-speed internet. 438 438
Now, this is going to cost you more 439 439
than an equivalent home fiber, cable, or DSL service though 440 440
but since you're in a remote area, 441 441
satellite might be your only option here. 442 442
Now, remote users are one area that satellite is used 443 443
but the real place where satellite service 444 444
really makes its mark is for mobile users on the go. 445 445
If you're somebody who's working out of an RV 446 446
or a truck in the middle of the oil fields of Texas, 447 447
this might be a great place to use satellite, 448 448
or if you're a business traveler like me, 449 449
you can be flying around the world on a commercial airplane 450 450
or taking a cruise across the ocean 451 451
and still remain connected to the internet the entire time. 452 452
For example, a few years ago, I took a cruise 453 453
but I couldn't afford to be offline for 10 days 454 454
because I had to ensure I can answer student questions 455 455
if they came in. 456 456
So, while I was on that cruise ship, 457 457
I was able to get online for about an hour a day 458 458
and answer student questions 459 459
before I had breakfast in the morning. 460 460
This is because the ship had WiFi 461 461
but that WiFi was connected to satellite internet. 462 462
Now, it was a bit expensive to use this but it worked well 463 463
and the speeds were actually pretty darn good 464 464
with these newer satellite constellations they're using. 465 465
In fact, I was able to stream Netflix and Hulu movies, 466 466
and television shows, and answer student questions, 467 467
and do all that with no problem. 468 468
It was very much like sitting back at home 469 469
and using my cable modem. 470 470
Now, satellite internet does have some drawbacks though. 471 471
First, the speed is not going to be as fast as a fiber modem, 472 472
or a microwave link, or even a cable modem. 473 473
Now, second, it's pretty expensive 474 474
for most satellite internet providers 475 475
compared to these other options you have. 476 476
And third, there's a good amount of latency 477 477
in the internet connection when you're using satellite. 478 478
This is because communication satellites for the most part 479 479
are using geosynchronous satellites 480 480
located about 22,000 miles away from the earth. 481 481
Now, what happens is you're going to send the signal up 482 482
really, really high, 483 483
and that takes 1/8 of a second 484 484
to go all the way up to space. 485 485
Then, it takes another 1/8 of a second to go down 486 486
to your internet service provider's ground station. 487 487
Then, it connects to the internet and gets your data, 488 488
and it goes back up to the satellite, 489 489
another 1/8 of a second, and then down to you, 490 490
another 1/8 of a second. 491 491
So, that round trip is going to take about 500 milliseconds 492 492
or half a second to complete. 493 493
For comparison sake, my microwave link 494 494
only has a latency of about 5 milliseconds, 495 495
100 times faster. 496 496
So, if you're a big video gamer, 497 497
that 500 millisecond latency will simply kill you 498 498
time and time again. 499 499
Now, when it comes to satellite, 500 500
things are rapidly changing from 2020 to 2025. 501 501
Many companies 502 502
are racing into the satellite internet market, 503 503
especially in the direct-to-consumer space. 504 504
SpaceX with their Starlink is a major player, 505 505
having already launched over 1,700 satellites 506 506
and gaining regulatory approval 507 507
to launch up to 12,000 satellites in total. 508 508
Now, Starlink is a low cost option 509 509
for many consumers as well with their monthly service 510 510
being only about $100 to $200 per month 511 511
but the best part is they've gotten their latency down 512 512
to about 30 to 35 milliseconds. 513 513
So, how did they do this? 514 514
Well, they chose not to use geosynchronous orbits. 515 515
You see, when you're in geosynchronous orbit, 516 516
you only need about three to six satellites 517 517
to fully cover about 90% of the earth, which is really good, 518 518
but you have to be further out from the earth 519 519
to be able to maintain line of sight 520 520
with all of those areas. 521 521
From 22,000 miles away, 522 522
you can see about 1/3 of the earth with a single satellite. 523 523
Now, Starlink on the other hand 524 524
has opted to use low earth orbits, 525 525
which is only about 340 miles from Earth. 526 526
This is much, much closer, 527 527
and this is how the latency is reduced 528 528
because it has to travel less distance. 529 529
So, the trade-off here is they now have a much smaller area 530 530
with each individual satellite. 531 531
For Starlink, each individual satellite 532 532
can only cover an area of about 350 miles on the ground 533 533
or around 563 kilometers. 534 534
This is why Starlink needs to have a lot of satellites 535 535
to fully cover the world and provide service 536 536
and that's why they're launching about one satellite a day 537 537
to be able to meet this demand. 538 538
Now, the final wireless connection we need to discuss 539 539
is known as high-frequency radio or HF radio. 540 540
Now, radio frequencies 541 541
are based on the different country regulations 542 542
of where you're going to operate in 543 543
and this can determine 544 544
which frequencies you can actually use. 545 545
For example, there are these old high-frequency 546 546
or HF networks that used to be used by ham radio operators 547 547
that are still being used today 548 548
but did you know these same radio frequencies 549 549
can actually run a high-speed packet network over them? 550 550
Now, high-speed packet is really kind of a foolish term here 551 551
because they're not that high speed. 552 552
They're actually only about 9,600 bps or 9.6 Kbps. 553 553
Yes, these are actually very, very slow networks 554 554
but when they were created, 555 555
they were considered a high-speed packet network. 556 556
Now, we can run some basic data over them, 557 557
like a chat room, or maybe send an email or two 558 558
but that's about it. 559 559
Usually, these high-frequency radio networks 560 560
are going to be used for very special use cases, 561 561
such as in a disaster relief scenario 562 562
or a military situation 563 563
but they are a valid wireless WAN connection 564 564
that you need to be aware of. 565 565
All right, I know we covered a ton of information 566 566
here in wireless WAN types. 567 567
Now we covered things like cellular, and microwave, 568 568
and satellite, and high-frequency radio. 569 569
Remember, as you're trying to determine 570 570
what the best WAN solution is for your networks, 571 571
you need to consider each of these wireless WAN connections 572 572
because they may be right 573 573
given your use case or your scenario.