902 – 928 MHz (DLM108)

SISO Broadband Radio Transceiver with miniPCI interface

DLM108 is a state-of-the-art embedded OFDM SISO (Single Stream) Wireless Broadband radio transceiver for the 902-928 MHz band. It is a member of large family of form factor compatible modules in different frequencies spanning from 400-1200 MHz. It contains all the digital and anologue/RF functions packed in a compact miniPCI size to simplify the system integration.

Band Availability and Radio Services

DLM108 Front_Edited

The ITU has allocated the 915 MHz band as unlicensed band for Region 2 (Americas). In USA, FCC Part 15 allows operation of unlicensed communication devices. Israel, Australia, New Zealand also allow use of the 915 MHz band. Countries like Brazil have certain special restrictions on the use of this band. DLM108 is able to support these special requirements.


The DLM108 broadband radio transceiver can deliver IP based 4K Video, Voice and Data services in Near Line of Sight (NrLOS) conditions. The transceiver delivers high Tx power, low distortion EVM (Error Vector Magnitude) signal even at 64 QAM modulation to achieve high data throughput. DLM108 features Doodle Labs’ proprietary Prism-WiFi® technology with advanced filtering and noise reduction techniques for better Rx sensitivity, high SNR and high interference immunity. Due to the high signal penetration at low frequency, DLM108 is specially suitable to deliver best performance in long-range NrLOS applications.

Interference Immunity

In USA, the high energy Paging towers operate just outside the 902-928 MHz band. The DLM108 transceiver features advanced filtering techniques to provide protection against this strong interference.

DLM108 Desens

Key Features
  • Best-in-class radio performance with high throughput, spectral efficiency, advanced RF interference mitigation and resistance to multi-path fading for Near Line of Sight (NrLOS) performance.
  • High Tx power to maintain distortion free signal (low EVM) to maintain lowest packet errors to maximize data throughput at higher data modulation.
  • Integrated LNA to achieve better Rx sensitivity and SNR.
  • Advanced filtering techniques to achieve high interference immunity.
  • Self-adapting OFDM modulation rates to maintain optimal link performance under different operating conditions.
  • An extensive family of form factor compatible radio modules in all frequencies spanning 400-1200 MHz.
  • 128 bit AES encryption for over the air data security
  • Simple System Integration with commercially available components.
  • Proven compatibility with OpenWrt and many other 3rd party software stack
  • Open Source ath5k Linux Kernel driver
  • Designed and Verified to meet various regulatory requirements.
  • Form factor compatibility with many embedded SBC (Single Board Computers).
  • High quality design ensures durability in harsh operating environments
System Integration

As shown in the block diagram, the modular nature of the Prism-WiFi radio transceivers allows for accelerated development of the wireless modem. The Prism-WiFi transceivers operate just like standard Wi-Fi modules and are drop-in replacements.


With the use of Prism-WiFi transceivers, it is easy to embed a wireless modem in any system. Any embedded Single Board Computer with standard miniPCI Type III A interface is required. These SBC are available from many vendors and they come in various sizes and I/O configurations. The Linux distribution OpenWRT has evolved over time and now provides advanced features in a wireless router. It is a very stable distribution and many OEMs are using OpenWRT. The distribution includes the ath5k driver to interface with the Prism-WiFi transceivers. Both OpenWRT and ath5k driver have extensive documentation available.

Each Prism-WiFi transceiver model uses a corresponding frequency offset from the standard WiFi frequency bands. This allows to effortlessly introduce modems targeted for various frequency bands by just installing a different transceiver. We are happy to consult with our customers and help select the correct operating frequency to suite the application.

Model No. and Product Status DLM108. General Availability. 
RF Power Software configurable from 14 dBm to 30 dBm
Receive Sensitivity -96 to -72 dBm, depends on the Modulation and the Channel Bandwidth.
Channel Bandwidth Software selectable 5, 10 and 20 MHz channels
Operating Modes AP and STA modes to implement Point to Point, Infrastucture Point to multi Point, and Ad-hoc/Mesh networks
Radio Waveform An extension of IEEE 802.11 g
MAC Protocol TDMA with Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA, Qualcomm Atheros MAC – AR5414)
Wireless Error Correction FEC, ARQ
Linux Software Support OpenWRT (Wireless Router) and ath5k driver
Tx/Rx Specification  Radio Data Rate (Mbps) Typical TCP/IP data throughput Modulation Max Tx Power
(± 2 dBm)
Rx Sensitivity
(± 2 dBm)
5 MHz Channel 1.5 1.3 BPSK 30 -96
  6 4.3 16 QAM 30 -86
  12 7 64 QAM 24 -76
10 MHz Channel 3 2.5 BPSK 30 -95
  12 8 16 QAM 30 -82
  24 14 64 QAM 24 -73
20 MHz Channel 6 5.5 BPSK 30 -93
  24 17 16 QAM 30 -83
  48 28 64 QAM 24 -71
Input Signal Strength -40 to -80 dBm (Recommended), (Absolute Maximum=0 dBm)
Receiver LNA Gain +15 dBm
Receiver Adjacent Channel Rejection (ACR) >20 dB
Receiver Alternate Channel Rejection (ALCR) >40 dB
Receive chain Noise Figure +6 dB
Transmitter Out of Band Emissions (Meets/Exceeds FCC, ETSI, IC specifications)
Minimum -20 dBc (0.5*ChBW), -27 dBc (0.71*ChBW), -32 dBc (1.06*ChBW), -44 dBc (2*ChBW)
Transmitter Adjacent Channel Leakage power Ratio (ACLR) 
 Min 45 dB (Fc ± ChBW),    Min 50 dB (Fc ± 2*ChBW)
Transmitter Spurious Emission Suppression -40 dBc (Minimum)
RF Power control In 0.5 dBm steps. Accuracy of power control loop ±1 dBm
It is advantageous to use the smallest Channel Bandwidth that can support the Throughput and Range requirements. Smaller Bandwidths provide more channels to choose and avoid any interference issues. The system’s SNR is higher at smaller Channel Bandwidths. 
Host CPU Board Any CPU board with Industry standard 32 bits, 33 MHz miniPCI Type III A
Antenna Ports Two MMCX Ports (50 Ohms) for Antenna Diversity.
Operating Voltage 3.3 Volts (Optional 5 V configuration)
Power Consumption 7W @  30 dBm, in continuous data transfer mode
5W @ 24 dBm, in continuous data transmit mode @ 48 Mbps
2W in continuous data receive mode
0.9W in Sleep mode
Ambient Temperature  for transceiver (Operating) Industrial grade (-20°C to +70°C). Recommended for the Outdoor/MIL-SPEC compliant modem development (-40°C to +60°C) due to internal power dissipation. Verified cold boot operation. 
Dimensions 60 x 67 x 8 mm, approx. 40 grams. (CAD file available)
Regulatory Requirements Designed and Verified to meet various regulatory requirements. Formal testing and approval is required based on the Integrator’s particular host platform. The Integrator is also responsible for obtaining any other required regulatory approvals in target markets for the finished product.
RoHS/WEEE Compliance  Yes

* Specification are subject to change without prior notice.


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