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Abstract
An intelligent transport system open platform integrating the S-band Mobile Interactive Multimedia messaging return channel protocol over satellite (based on Enhanced Spread Spectrum Aloha) has been developed and tested under real environment conditions within the framework of SafeTRIP, an FP7 EU-funded project. This paper presents the first field trials results using the S-band Mobile Interactive Multimedia technology. The introduced forward and return link outcomes have been derived from mobile field trials carried out in the surroundings of the German Aerospace Center (DLR) in Germany. Finally the validation of the system performances has been realized thanks to the use of a traffic emulator that can simulate a large population of Enhanced Spread Spectrum Aloha terminals.
In this survey paper we review the Random Access (RA) techniques with particular emphasis on the issues and the possible solutions applicable to satellite networks. RA dates back to the 1970's when the ALOHA protocol was developed to solve the problem of interconnecting university computers located in different Hawaiian islands. Since then, several evolutions of the ALOHA protocol have been developed. In particular, solutions were devised to mitigate the problem of packet collisions severely degrading the RA protocols performance. The approach followed for many years has been to avoid the occurrence of collisions rather than solving them. More recently, techniques tackling the RA packet collision problem have appeared triggered by the need of improving RA performance in satellite and terrestrial wireless networks. In particular, satellite networks large propagation delay does not allow the adoption of enhanced terrestrial RA techniques based on channel sensing. Adopting conventional demand assignment multiple access protocols is not suitable for supporting a large number of sensors or devices transmitting small size low duty cycle packets as required for Machine-to-Machine (M2M) communications. This provided the stimulus to exploit Successive Interference Cancellation (SIC) schemes to solve packet collision issues. The use of SIC in RA is relatively new and has opened up a promising research area. We provide an extensive review of recent high performance RA techniques achieving more than three orders of magnitude throughput increase compared to the original ALOHA at low packet loss rate. In this survey we cover both slotted and unslotted techniques. Finally, we review the use of RA in satellite systems and related standards including recent proposals for M2M applications.
An open ITS platform combining interactive satellite services with other communication channels is being developed and evaluated in field trials within the SafeTRIP project [1]. Prototyping and in-field validation of a novel waveform for messaging return channel over satellite for land mobile is an important objective of the project. The overall system architecture has recently been standardized by ETSI under the name of S-MIM (S-band Mobile Interactive Multimedia). The messaging protocol, described in the Part 3 of the standard, is based on the Enhanced Spread Spectrum Aloha (E-SSA). Its main asset resides in the low power required at the transmitter, which will allow the reuse of off-the-shelf power amplifiers and low-cost omnidirectional antennas. This paper will present a comprehensive summary of previous E-SSA performance analysis from simulations and the first field trials results using the E-SSA waveform. The presented results have been derived from static and mobile field trials carried out in Germany with fully functional E-SSA modulator and demodulator prototypes and the EUTELSAT10A satellite. Results for the static and mobile performance of the E-SSA demonstrator with an omni-directional antenna under Line-of-sight (LOS) conditions are presented. The measured Packet Error Rates of transmissions via satellite at different terminal power levels confirm the theoretical link budget calculations for single and multiple simultaneously transmitting terminals. The degradation due to fading effects of the transmission channel under mobile conditions has been measured during the trials to approx. 3 dB. The resulting overall required transmitter power in the multi-user scenario of the trials setup has been only -3 dBW to reach a high QoS under mobile conditions. This value confirms the suitability of the E-SSA waveform for interactive mobile services for the mass market.
This paper gives an overview of a suitable communications system capable of efficiently use the available S-band allocation for pan-European Mobile Satellite Services (15 MHz in both uplink and downlink for each of the two licensed operators) to provide different classes of services such as interactive mobile broadcast services enhancing DVB-SH offer, messaging services for handheld and vehicular terminals, realtime emergency services such as voice and file transfer, mainly addressing institutional users on-the-move such as fire brigades, civil protections, etc... The design is based on a modular, flexible and scalable system architecture enabling different channelizations and frequency allocations within each beam, allowing independent deployment of different service classes within different beams, whilst ensuring backward compatibility with DVB-SH legacy terminals.
This paper describes the implementation of the first enhanced spread spectrum aloha demodulator, based on an innovative architecture which combines software-defined radio with processing via commercial graphics processing units. The validation tests performed both in laboratory conditions and directly on the satellite EUTELSAT 10A are presented. The performance assessment results obtained via satellite validate the theoretical results to a sufficient degree to make enhanced spread spectrum aloha technology a viable option for low-power mobile and fixed terminals, thus encouraging the growth of satellite mass market applications. Copyright © 2014 John Wiley & Sons, Ltd.
In this paper we present experimental results of the ETSI S-MIM (S-band Mobile Interactive Multimedia) protocol, tested for the first time over a real GEO satellite (EUTELSAT 10A) and through a fully compliant ground platform. In particular, the employed radio interface implements the Part 3 of the standard, i.e. the asynchronous access protocol, especially conceived for the interactive messaging services. The performance assessment done by satellite validates the theoretical results and opens the way for the exploitation of low-power mobile and fixed terminals, thus allowing the proliferation of satellite mass market applications.
The work presented here describes the key design drivers and performance of a high efficiency satellite mobile messaging system well adapted to the machine-to-machine communication services targeting, in particular, the vehicular market. It is shown that the proposed return link multiple access solution is providing a random access channel (RACH) aggregated spectral efficiency around 2 bit/s/Hz in the presence of power unbalance with reliable packet delivery over typical land mobile satellite (LMS) channels.
The manuscript describes the design drivers and performance of a high efficiency quasi-real time satellite mobile messaging system well adapted to the location-based and data acquisition services targeting in particular the automotive market. It is shown that the proposed solution is providing a random access channel throughput around 2 bit/s/Hz with reliable packet delivery over satellite mobile channels. This very high throughput is obtained by a relatively simple packet transmission control based on downlink signal quality observation and an optimized design of spread Aloha with successive interference cancelation (SIC) at the gateway.
This article presents a radio interface recently standardized by ETSI under the name of S-band Mobile Interactive Multimedia (S-MIM) and especially designed to provide ubiquitous messaging services over S-band GEO satellites using low-power terminals. Thanks to low terminal cost and high bandwidth efficiency, this standard allows the development of new satellite services, particularly for vehicular and machine-to machine applications. The S-MIM standard relies on a broadcasting radio interface such as DVB-SH or ETSI SDR in the forward link, and reuses 3GPP W-CDMA technology properly adapted to the scope in the return link. Thanks to the use of spread spectrum ALOHA, terminals can access the channel in a totally asynchronous manner. The use of a packet-optimized iterative successive interference cancellation (i- SIC) algorithm at the receiver allows exploiting the inherent power imbalance among terminals in order to boost the throughput with respect to conventional SSA systems. In addition, advanced packet transmission control techniques have been adopted to maximize the probability of successful packet reception in the challenging land mobile satellite channel. Finally, the S-MIM link layer provides efficient and reliable transport of IP datagrams over the forward and return link radio interfaces.
Recent trends in digital communications are opening commercial
applications to code division multiple access (CDMA). A novel access
technique based on bandlimited quasi-synchronous CDMA (BLQS-CDMA) is
described, showing all the advantages of synchronizing conventional
direct sequence CDMA to drastically reduce the effect of self-noise.
Bandlimitation is achieved with no detection loss by means of Nyquist
chip shaping, leading to a simple all-digital demodulator structure.
Detection losses due to imperfect carrier frequency and chip timing
synchronization are analytically derived and numerical results are
checked by computer simulations. Impairments due to satellite
transponder distortions are evaluated. The full digital modem structure
is presented, together with possible applications to mobile and very
small aperture terminal (VSAT) satellite communications
- S-Mim Field
- Results Copyright
S-MIM FIELD TRIALS RESULTS
Copyright © 2014 John Wiley & Sons, Ltd.
Int. J. Satell. Commun. Network. (2014)
DOI: 10.1002/sat
he has been Project Manager at MBI S.r.L. (Pisa, Italy) where he coordinates the S-band development activities. He has been the technical leader for MBI in several ESA and EU S-band projects
- Saturn Safetrip
- Denise Miresys
Marco Andrenacci received his Bachelor's Degree in Telecommunication Engineering at
the Pisa University in 1997. Since April 2008, he has been Project Manager at MBI S.r.L.
(Pisa, Italy) where he coordinates the S-band development activities. He has been the technical leader for MBI in several ESA and EU S-band projects (SAFETRIP, SATURN,
DENISE, MireSys, and J-Ortigia). He has over 10 years of experience in designing and
deploying telecommunication networks with heterogeneous transport technologies.
E-SSA demodulator implementation, laboratory tests and satellite validation. Special Issue Paper, submitted to
- M Andrenacci
- G Mendola
- F Collard
- D Finocchiaro
- A Recchia
Andrenacci M, Mendola G, Collard F, Finocchiaro D, Recchia A. E-SSA demodulator implementation, laboratory tests and
satellite validation. Special Issue Paper, submitted to International Journal of Satellite Communications and Networking,
2013
Implementation Guidelines, V1.3.1 AUTHORS' BIOGRAPHIES
- Dvb-Sh
DVB-SH Implementation Guidelines, V1.3.1
AUTHORS' BIOGRAPHIES
E-SSA demodulator implementation laboratory tests and satellite validation.Special Issue Paper submitted to
- Andrenaccim Mendolag Collardf Finocchiarod Recchiaa
Performance of the S-MIM messaging protocol over satellite 6th Advanced Satellite Multimedia Systems Conference
- A Recchia
- Collard
- Antip
Methods apparatuses and system for asynchronous spread-spectrum communication. European Patent Application nr
- Del Río Herreroo De Gaudenzir
Performance of the S-MIM messaging protocol over satellite
- Antipn Recchiaa Collardf