UDP seadistus COFDM transiiveril

COFDM Module Experiments

General Conditions
• Two (or three) COFDM modules.
• Bandwidth: 4 MHz wideband.
• Modulation settings:
• FEC: 5/6
• Modulation type: QPSK
• Guard interval: 1/4
• Traffic parameters:
• Protocol: UDP broadcast
• Packet size: 1024 KB
• Transmission rate: 100 packets per second
• Antennas are suitable for the frequency range and in good condition.
• Modules are verified to be functional.
• Multiple frequency configurations tested — the same problem occurs in all cases.
• Typical measured parameters during tests:
• SNR ≈ 25 dB
• RSSI ≈ -25 dBm
• Issue appears only during bidirectional traffic (data sent in both directions simultaneously).
• No packet loss during unidirectional traffic.

Experiment 1

Konfiguratsioon:
• Module 1:
• TX = 3180 MHz
• rx = 570 MHz
• Module 2:
• TX = 570 MHz
• rx = 180 MHz (Downverteri kaudu 3000 MHz nihke)

Tulemus:
• Kahesuunaline liiklus: Paki kadu täheldatud.
• Ühesuunaline liiklus: Paki kaotust pole.

Experiment 2

Konfiguratsioon (sama ribalaius, erinevad sagedused):
• Module 1:
• TX = 800 MHz
• rx = 570 MHz
• Module 2:
• TX = 570 MHz
• rx = 800 MHz

Tulemus:
• Identne katsega 1 - Paki kaotus kahesuunalise liikluse ajal.
• Ühesuunaline liiklus: Paki kaotust pole.

Experiment 3

Konfiguratsioon:
• Kaks eksperimendi moodulit 1.
• Täiendav kolmas moodul, mis on konfigureeritud ainult Rx jaoks 570 MHz.

Tulemus:
• Kui kaks esimest moodulit vahetavad andmeid kahesuunaliselt, Kolmas Rx-moodul kogeb ka pakettide kaotust.
• Kui liiklus on kahe esimese mooduli vahel ühesuunaline, Ühelgi vastuvõtjal pakkide kadu ei täheldata.

Järelduste kokkuvõte

1. Paki kadu toimub ainult samaaegsete kahesuunaliste edastuste ajal.
2. Kaod mõjutavad ka sõltumatuid RX-i vastuvõtjaid, kes tegutsevad samal sagedusel.
3. SNR ja RSSI jäävad teema ajal normaalseks.
4. Probleem on sagedusest sõltumatu ja ilmneb koos sageduse alam muunduritega ja ilma.

Palun kontrollige UDP paketi suurust, 1024KB on liiga pikk.

COFDM transceiver one-way transmission UDP Experiment 1

Setup:
● Module 1: RX = 740 MHz, TX = 850 MHz.
● FEC – 1/2
● QPSK
● Guard – 1/32
● Power attenuation – 0
● Bandwidth – 2 MHz
● Data rate = 100 packets/s, each packet 1024 KB.
Test description:
● unicast data was transferred in both directions at the same time
Tulemus:
● When both modules transmitted in both directions at the same time,
packet loss occurred
● When data transfer was one-way only, Paki kaotust pole

Setup:
● Three COFDM modules were used
● FEC – 1/2
● QPSK
● Guard – 1/32
● Power attenuation – 0
● Bandwidth – 2 MHz
Test description:
● Module 1 transmitted unicast
● Module 2 transmitted broadcast at the same time as Module 1
● Module 3 only received the broadcast from Module 2
Tulemus:
● With simultaneous unicast and broadcast transmission (Modules 1 ja 2
active), Module 3 experienced packet loss while receiving broadcast data
from Module 2
● When only broadcast transmission was active (without concurrent
unicast), Module 3 received data without packet loss

Setup:
● Four COFDM modules were used.
● Parameters consistent with previous experiments
Experiment description:
● Module 1 transmitted a broadcast to Module 2
● Module 4 transmitted a broadcast to Module 3
● Links were independent, and transmission was at the same time
Observation:
● Both receiving modules (2 ja 3) received their data streams without any
packet loss
RESUME: I think we have a hardware problem with the TX part of your
module. When we have TX and RX at the same time, the TX does not transmit
all packets, and we get a packet lost. The problem may be in the bus; sa saad
not read and write data to your TX and RX submodules at the same time