Energy-Efficient Technologies for the Dismounted Soldier (1997) / Chapter Skim
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6 Networks, Protocols, and Operations
6 Networks, Protocols, and Operations
Pages 112-130
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From page 112... ...
Military adaptations of commercial cellular and PCS technologies could reduce power requirements for the dismounted soldier and enable the Army to keep pace with commercial technology more economically. Several large scale commercial satellite-based PCS networks will be available for consideration as military assets in the next few years that could support widespread operations by dismounted soldiers with limited power sources.
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From page 113... ...
Mitigation techniques involve either averaging over these variations or attempting to avoid them. Error correction coding, time interleaving, and direct-sequence code division multiple access (CDMA)
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From page 114... ...
Practically speaking, even the extremely complex signal processing that will be available in 2015 will probably not petit SNRs below ~ or 2 dB for useful error rates; thus, energy requirements will be reduced, at most, by a factor of five. Together with the previous factor of four increase in transmitter efficiency, the achievable energy efficiency of stateof-the-art wireless information transmission will increase, at most, by a factor of 20 in the future.
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From page 115... ...
The characteristics of the propagation environment will limit improvements and determine the amount of signal processing needed to attain these improvements. At the present time, the interaction between antenna and medium characteristics is not well understood, and research in this area may lead to significant gains in overall energy efficiency.
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From page 116... ...
The figures in Table 6-3 also suggest the potential benefits in terms of energy consumption of multihop system architectures, which are described later in this chapter. LAND WARRIOR SYSTEM The Land Warrior system includes radios for communications, a GPS (global positioning system)
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From page 117... ...
The various subsystems can be placed in standby modes either automatically or manually, so the duty cycle of each subsystem is critical to determining battery life and overall power requirements. The duty cycles are largely determined by network architectures, communications and computing protocols, and operating doctrine.
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From page 118... ...
A base station typically includes more processors, RF circuitry, antennas, and consequent energy demand than the terminals, so the hierarchical structure works to reduce the power requirements of the terminal equipment. Figure 6-2 shows a peer-to-peer network, which is representative of the radio communications networks for Land Warrior.
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From page 119... ...
Base stations would collect pages, and when enough of them had accumulated (about every minute) , the base station would activate its carrier.
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From page 120... ...
Figure 6-4 illustrates, in simplified form, the protocol used by the SINCGARS radios that wall be required for the squad radio and is contemplated for soldier radios. This type of peer-to peer network does not involve call setup protocols, which can take several seconds before a conversation can begin.
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From page 121... ...
Power requirements of the soldier and squad radios for Land Warrior could be significantly reduced with protocols and network architectures that permit receivers to sleep a large percentage of the time, but the simultaneous requirement for low latency presents a serious problem. Protocols that place larger complexity and power requirements on the transmitter while substantially reducing the complexity and power requirements on the receiver may be possible.
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From page 122... ...
As explained earlier, PCS technologies are primarily based on hierarchical networks with fixed base stations and mobile terminals, while the Land Warrior system is planned as primarily a peer-to-peer network. A hybrid network, in which a hierarchical architecture provides "virtual" peer-to-peer capabilities, could reduce the power requirements for wireless communications for future soldier systems and meet the same functional requirements as a true peer-to-peer communications network.
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From page 123... ...
SELECTING A SUITABLE COMMERCIAL TECHNOLOGY The next question is how commercial PCS technologies can be adapted for a hybrid network (to provide virtual peer-to-peer capabilities) because all commercial technologies use fixed hierarchical architectures.
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From page 124... ...
. The near-far CDMA problem with IS-95 is managed by centralized feedback power control of the mobile transmitters and by soft handoffs between base stations, which must be executed when terminals cross boundaries between the coverage areas of adjacent base stations to prevent loss of access.
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From page 125... ...
Significant reductions in power for soldier systems are possible by designing protocols to support a hybrid network based on an adaptation of commercial technology. The availability of highly optimized components for wireless terminals from the commercial sector, which wall accelerate in coming years, should help to reduce power requirements.
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From page 126... ...
The SINCGARS radio protocols will clearly be incapable of meeting future communications needs above the squad level; their capacities are already stressed by existing needs for voice communication. However, the SINCGARS technology will be widely deployed for at least 10 years.
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From page 127... ...
Unmanned Aerial Vehicle Systems and Architectures A potential architecture that would capture the benefits of both terrestrial and satellite-based networks would place "base stations" on high-flying unmanned aerial vehicles, which would fly over the area in which wide-area
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From page 128... ...
OPERATIONAL CONSIDERATIONS One of the most important steps the Army can take to reduce energy use by the dismounted soldier is to develop protocols and software capabilities that address power discipline in an operational context. Notwithstanding advances in micro-electronics and in optimizing energy supply and demand, the problem of power discipline, which the Army must address from the level of the soldier and the organization in which he functions, remains.
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From page 129... ...
· Better understanding of the interaction between the harsh radio propagation environment and antenna and signal processing characteristics could lead to significant gains in energy efficiency for wireless soldier communications systems. Multihop wireless networks based on COTS wireless technology offer the benefits of energy efficiency, reliability, and reconfigurability.
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From page 130... ...
The adaptation of wideband commercial satellite technologies should take into account the military need for even smaller and more mobile antennas. Airborne platforms offer a way to reduce energy consumption by extending radio transmit ranges.
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