The MPU5 radio is a mesh network radio capable of transmitting voice, data and position location information (PLI) throughout the battlefield, to include subterranean, urban, desert and dense forest environments. 3rd Brigade Combat Team, 101st Airborne Division (Air Assault) successfully integrated MPU5 radios into their winter Field Training Exercise (FTX) (spanning across three state boundaries, and two time zones), brigade live fires, multiple battalion task force air assaults, and offensive and defensive operations during the Joint Readiness Training Center 19-05 rotation at Fort Polk, La.

Operations executed during both the FTX and JRTC 19-05 tested the radios capabilities in subterranean, wooded and urban environments with great success. The MPU5 radio seamlessly passed communications and PLI between ground units, air assets and command posts.

Infantry battalions were able to command and control units on the ground during the initial ground assault force (GAF) from Peason Ridge into "the box." The MPU5 passed voice, text and PLI from the ground units to TACs and TOCs up to 25 kilometers away. The battalion TACs located closer to the assault force received voice transmissions created by the digital mesh network and line of sight (LOS) antennas. The TOCs located 20-25 kilometers away received voice and data from the ground force through the MPU5 SPOKE (router). The MPU5 radio network uses the best transmission medium available to pass data through the radio network to the other MPU5 devices. The radio will select the best path which is transparent to the operator.

The MPU5 SPOKE is critical to the effective implementation of the digital mesh networking of MPU5 radios during offensive operations. The MPU5 SPOKE allows units to rapidly advance across the battlefield without the limitation of LOS communications ranges. One example occurred during the FTX when 1st Battalion, 187th Infantry Regiment, 3rd Brigade Combat Team, 101st Airborne Division (Air Assault) was able to communicate from Fort Knox, Ky., to Muscatatuck Urban Training Center (MUTC) in Butlerville, Ind. during an aerial scout infiltration. The radio is programmed to switch from LOS transmissions to SPOKE-SPOKE transmissions transparent to the user. A second successful demonstration of this capability occurred during the initial GAF into "the box" at JRTC, where there was zero loss in tactical communications during this infiltration. The distances reflected during the training events above do not fully demonstrate the full capability provided by the MPU5 SPOKE. Bottom line, with MPU5 spokes integrated into any radio mesh, distance limitations between units become irrelevant.


1. JRTC 19-05 demonstrated a few limitations of the MPU5 radio system. The MPU5 radio mesh network consists of several pieces of hardware: MPU5 radio, the SPOKE (Cisco Router), tether cables, end user devices, headsets and a TOC kit. The two pieces of hardware which stood out as limiting factors were the SPOKE and the tether cables.

First, the fragility of the SPOKE systems were an issue. The SPOKE is a plastic router that allows MPU5 data to use the cellular network expanding the maximum range of voice and data transmissions. On two separate occasions, subordinate units damaged the SPOKE systems which reduced the range of the radios to standard FM ranges (up to 5km). The damaged SPOKE systems significantly reduced the utility of the MPU5 radios in instances where platoons were geographically dispersed on the battlefield, outside of the 5km bubble. The second piece of hardware that limited the utility of the MPU5 were the tether cables which were easily damaged. The tether cables allow the MPU5 radios to connect and transmit through other radio systems, such as the RT-1523 or AN/PRC-117G/F.

2. Additionally, we identified a significant training gap in one of the two battalions equipped with the MPU5s where operators failed to properly connect the tether cables and switching to dual channel, thereby limiting the full capability of the MPU5 radio while at JRTC. The second infantry battalion which received training prior to the BDE FTX in December and during RSOI at JRTC demonstrated better implementation of the radio systems. Operators in this battalion received approximately 8-16 hours of instruction directly from the vendor. Operators felt that 8-16 hours was adequate training time for the MPU5 radio, End User Device (EUD) and SPOKE. Units should plan this period of instruction into their training plans to maximize the full capabilities of the MPU5 radio system.

3. Power proved to be a significant limiting factor for company-level and below elements. Although the MPU radio batteries could last between 10-12 hours on a full charge, the SPOKE required approximately five 5590 batteries in a single 24-hour period. Power generation at this intensity was not sustainable for most company and below elements during the 14 day decisive action rotation. Company units frequently had to rotate through the battalion S6 charging station to sustain battery power on the MPU5 SPOKEs. One of the companies utilized solar panel chargers to recharge batteries. However, this process was slow and not sustainable during the tempo of combat operations.


1. Ruggedize the SPOKE to reduce the risk to damage by operators. The aluminum Cisco router is probably a viable option for vehicular applications, but for dismounted purposes it is both not rugged enough and consumes too much power. Engineer a durable solution with the ability to withstand standard combat operations performed by units at the company level and below. Improving the durability will increase the reliability of the MPU5 radio network.

2. Unit leaders stated a lack of training as a shortfall for MPU5 implementation. Since this was a vendor-only supported exercise, meaning Persistent Systems agreed to provide training, equipment, and support on a condensed timeline, adequate training was not possible for one battalion. Recommend a full training plan implemented prior to major training events especially to all battalion S6 25Us, unit leaders, and radio telephonic operators (RTOs). Training focus should include basic radio operations, EUD configuration management and planning factors. Bottom line, if a unit allocates training time far enough in advance for the above recommended personnel, they will be very successful with the implementation of this radio system into their PACE plans during operations.

3. Develop a power solution reducing the 5590 battery requirement. Recommend a better charging solution or more efficient batteries for the MPU5 radio to sustain long durations during exercise and combat operations, especially in austere environments where power generation is sparse.

4. Highly recommend that the vendor develop a way to achieve cloud connectively without the need for a Cisco router, requiring only an LTE modem such as a ruggedized cradle point.

Way Ahead/Rakkasan Proposed Solutions

MPU5 radios are currently capable of integration into currently fielded TOCNET software (SoftCAU). This capability allows command posts with a Command Post Platform (CPP) truck to connect to a MPU5 radio and project radio transmissions throughout the command post. Users at the command post would be able to monitor radio nets and transmit to radios on the battlefield from their computers. This would facilitate quicker information dissemination throughout a command post and across the battlefield. Additionally, if units can integrate the MPU5 radio into the Combat Net Radio (CNR) Gateway utilizing their organic Tactical Communications Node (TCN) then voice transmissions can traverse the entire tactical network to any command post on the battlefield. In either of these solutions, the limiting factor is only voice transmissions can be projected onto the entire battlefield.

Another solution (still in conceptual design) may provide a better way to integrate the data and PLI capabilities of this radio system which involves tethering the MPU5 SPOKE to Global Rapid Response Information Package (GRRIPs). Tethering the MPU5 SPOKE to the GRRIPs allows for the data and PLI to traverse to any other GRRIPs in either the Unclassified or SIPR network. The diagram below demonstrates how the GRRIPs can be used to pass data and PLI to the tactical SIPR network and down to the TOCs and TACs at various echelons. Transmission possibilities for this concept is not just limited to GRRIPs. MPU5 SPOKES can be tethered to transport mediums such as Satellite Transport Terminal (STT) or SMART-T via standard Ethernet connections. Recommend that Persistent Systems works with these other Program Management offices and other Army units to develop solutions for integration of the MPU5 radio system into their tactical networks.

PLI data is key to clearing air and ground prior to strikes but MPU5 PLI data is currently limited to specific COP tools. Another solution is for MPU5 PLI data to pass through the Mission Command NOC and populate on JBC-Ps and utilizing Data Dissemination Service (DDS) can populated into Command Post of the Future (CPOF). This technical solution will allow redundancy in the COPs for units below battalions that don't have CPOF. PLI data currently populates on the TAK server along with ATAK and WINTAK devices.


The MPU5 radio system provides regular Army units with redundant transmission means for communications within the same radio package (i.e. LOS, 4G/LTE, GRRIPs, etc.). The mesh network created by each individual radio allows units in subterranean and dense urban environments to communicate effectively with voice, data and PLI. The SPOKE adds the additional capabilities for Commanders to mission command lethal platoons and squads beyond line of site communications without the need to establish numerous Retransmission sites (RETRANS), as required by FM radios. Consequently, the MPU5 radio/SPOKE combination reduces the need for RETRANS personnel and assets on the battlefield increasing survivability and reducing security requirements throughout the battlefield.

The consensus from the field usage is that the MPU radios provided reliable communications for infantry units in combat operations. The ease of use of the radio coupled with the EUDs hosting ATAK was very beneficial to combat operations at the platoon and squad level as well as battle tracking at the company and higher levels. Capt. Ciampa, Commander of Angel Company 3rd Battalion, 187th Infantry Regiment 3rd Brigade Combat Team, 101st Airborne Division (Air Assault) stated that he was able to battle track in real-time and know exactly where his platoon leaders were on the battlefield with just a quick glance at the EUD screen. Additionally, one infantry platoon reported that the clarity and low squelch signature allowed for surreptitious reporting even when the enemy was less than 75 meters from their position. Both commanders from 3rd Battalion, 187th Infantry Regiment 3rd Brigade Combat Team, 101st Airborne Division (Air Assault), Capt. Ciampa and Capt. Stephan Townes (Commander of Battlehard Company) highly recommend a radio system of this type to any light infantry unit that maneuvers dismounted over great distances in severe terrain.

By: Capt. Matthew Harrison, 3rd Brigade Combat Team, 101st Airborne Division (Air Assault) Assistant S6 and Maj. Tyrone Streifel, 3rd Brigade Combat Team, 101st Airborne Division (Air Assault) S6