SOLECTEK KM Series 10Gbps Microwave Link Long Range 240MHz XPIC • Two Dual-Transceiver radios on one side (side by side, single mount) • Special branching circuit to combine all signals. • One single-pol antenna – direct mount up to 6FT antennas • Data and header compression – allows up to 20% increase in capacity • Link Capacity will reach almost 10Gbps.

1. KM Series
10Gbps Microwave Link
January, 2020
v 1.0

2. Achieving multi-gigabit wireless links
• Wireless link Capacity is primarily determined by two parameters
– Channel BW
– Modem Modulation
• Channel BW – The capacity is directly proportional to the channel size. Doubling of
channel BW doubles link capacity. There is a Rx sensitivity loss for larger channels,
but in general it is considered to be a small price to pay for big gains.
• Modulation – higher order modulations will increase the link capacity by increasing
the bit efficiency of the modem. Typically, you gain 10 to 20% by increasing an order
of modulation. However, there is a penalty in link budget in terms of both Tx power
reduction and Rx sensitivity loss for higher order modulations.
• The trick is to balance the channel BW, modem modulation, antenna size to achieve
the performance you desire.
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3. Problems with E-Band
• E-Band (70/80GHz) – huge bandwidth (5GHz BW at 70GHz and 80GHz) allows
10Gbps products. There are several products in the market.
• Problem – E-Band is subject to severe rain fade, which already limits to a short
distance. High order modulations (64QAM to 256QAM) needed for 10Gbps further
cut down on the link budget
• RESULT – reliable link distance at 10Gbps is limited to 1 mile.
• Antenna size is limited to 2FT due to already very narrow beamwidth of 0.5 degree.
Any larger antenna to get more antenna gain would be extremely difficult to align.
• Bottom line – E-Band can be used in very short-haul links in dense urban areas, but
not for PTP backhaul applications that go beyond 1 mile.
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4. Problems with Microwave
• Faces different problems from E-Band in large capacity links.
• Typically go long distance at 6 and 11GHz (even at 18GHz)
• Rain fade is small to modest and link budget for a microwave link is relatively good even
with 2048QAM.
• Antenna size – typically 2 to 6FT, but 10 FT size is available if you want to maximize the
antenna gain for long distance links.
• Problem – small channel sizes. Often, maximum channel BW at microwave frequency
bands is 56MHz (ETSI) and 60/80MHz (ANSI).
• RESULT – In order to increase the link capacity, you need to get many channels and deploy
multiple links with multiple antennas. This means very high cost of hardware and
complicated installation with big footprint on the tower.
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5. Typical Microwave Link Capacity
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• Single carrier radio – generally tops at ~ 500Mbps in single channel use (60 to
80MHz)
• 4+0 can get up to 1-2 Gbps, but beyond 4+0 requires multiple radios and antennas,
which means higher degrees of complexity in equipment configuration, large foot
print installation, and very high costs.
Link Capacity for Single Carrier 1+0
28MHz 40MHz 56MHz 60MHz 80MHz
QPSK 35 48 67 72 97
16QAM 72 93 131 140 195
32QAM 95 128 179 192 257
64QAM 118 158 221 237 318
128QAM 141 189 265 284 379
256QAM 164 229 308 330 440
512QAM 187 259 350 375 502
1024QAM 219 281 393 421 564
2048QAM 233 312 437 468 624
Link Capacity for 4+0 or 2 x (2+0 XPIC)
28MHz 40MHz 56MHz 60MHz 80MHz
QPSK 139 192 269 288 388
16QAM 288 373 522 559 780
32QAM 380 512 717 768 1028
64QAM 472 632 885 948 1272
128QAM 564 756 1058 1134 1516
256QAM 656 880 1232 1320 1761
512QAM 748 1000 1400 1500 2008
1024QAM 840 1124 1574 1686 2254
2048QAM 932 1248 1747 1872 2496

6. The case for ultra wide channels
• With 4 x 60MHz channels with V/H
XPIC, 4 radios links are needed. This
is equivalent to 8+0 with 60MHz BW.
• If 120MHz wideband channels are
used, you can reduce the radio links
from 4 to 2, while achieving the
same capacity.
• If 240MHz ultra wideband channels
are used, only one radio link is
needed.
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7. Link Capacity with Ultra wide channel with XPIC
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• Single carrier radio – generally tops at 500Mbps in single channel use (60 to 80MHz)
• Use of four channels (4+0) allows gigabit or higher capacity in many reasonable
combination of modulation and channel BW (ex: 56MHz BW and 128QAM = 1Gbps)
• Short link with maximum settings – 4Gbps with a single radio link !
Link Capacity for Ultra wideband XPIC
112MHz 160MHz 224MHz 240MHz
QPSK 268 388 536 576
16QAM 522 780 1044 1118
32QAM 716 1028 1432 1536
64QAM 884 1272 1768 1896
128QAM 1058 1516 2116 2268
256QAM 1232 1760 2464 2640
512QAM 1400 2008 2800 3000
1024QAM 1574 2256 3148 3372
2048QAM 1748 2496 3496 3744
4096QAM 1908 2724 3816 4088
Note: 4096QAM will be released as a future update.

8. Hardware Configuration – 240MHz XPIC
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• Dual Transceiver Radio with 2+0 XPIC
• Use only one single-pol antenna (OMT is built into the radio unit)
– Direct mounting of radio to back of antenna up to 6FT antenna size (above left)
– Use flex twist waveguide and remote mount for radios if larger antenna sizes are
needed. (above right)

9. Space Diversity
• Dual receivers for each path – pick the better of the two signals at
receiver
• Useful with long links that have a body of water in the middle of
the path (reflective surface)
• Transmit section remains the same, so there is no need for
additional channel licenses.
• Does require additional set of antennas, so the configuration of
hardware is much more complex.
• The benefit – for a given reliability figure, higher order
modulations can be used so link capacity will be increased.
• Space diversity is possible with one dual-transceiver radio, but the
second radio must be used for diversity purpose, so it cuts down
on the capacity by half, but it does allow higher order modulation
to be used. The result is mixed.
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10. For the case of 2 x 240MHz Channels
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• Two Dual-Transceiver radios on one side (side by side, single mount)
• Special branching circuit to combine all signals.
• One single-pol antenna – direct mount up to 6FT antennas
• Data and header compression – allows up to 20% increase in capacity
• Link Capacity will reach almost 10Gbps.