Enhanced spread spectrum ALOHA system level performance assessment

Abstract

This paper describes the simulated system performances of the enhanced spread spectrum ALOHA (E-SSA) random access scheme in a realistic mobile satellite multibeam scenario operating in S-band. The E-SSA random access scheme has been selected for supporting messaging services in the ETSI S-band Mobile Interactive Multimedia (S-MIM) standard. Finally, the operation and the performance of E-SSA is elaborated in the context of a terrestrial gap-filler component complementing the satellite coverage in densely populated areas. It is shown that the terrestrial network is able to off-load traffic from the satellite component while ensuring continuity of service in areas that cannot be covered by a satellite only system. ‡ Although orthogonal frequency division multiplexing (OFDM) technology might be even more efficient in such frequency selective environments; it appears less suitable for use in random access schemes. MHz is available in S-band for mobile satellite communications. In Europe, two licenses were given to Inmarsat and Solaris for operating in such bandwidth, each one having an allocation of a 15-MHz band. ¶ We ignore here the effect on capacity deriving from the limitation of an on-board feeder link (satellite-to-gateway) radio frequency power. This is justified for a bent-pipe star satellite architecture where a sufficiently large gateway antenna makes the feeder downlink carrier to noise ratio much higher than the user-to-satellite uplink. E-SSA SYSTEM LEVEL PERFORMANCE † † † The residual (noncanceled) power is dominated by the power in the other signals paths (which were not correctly detected and thus canceled). For example, in Rec. ITU-R M.1225 Vehicular Channel A model, the four weakest paths (out of a total of six paths) contribute to 27% of the overall received signal power. So assuming we were only able to correctly detect the two strongest paths, we would have a 27% residual (not canceled) power. 498 G. GALLINARO ET AL.

Cooperative Slotted Aloha for Multi-Base Station Systems

“…This is a common approach in random access and specially slotted Aloha with SIC, e.g., [2], [3], [11], [24], [17], [18]. It is worth noting that this paper (with our prior papers [27], [28], [29]) and [26] (where the latter does not provide analytical studies) are pioneering works on slotted Aloha with SIC for multi-base station systems. As such, our paper naturally focuses on the MAC model.…”

Enhancing Contention Resolution ALOHA Using Combining Techniques

“…This approximation takes into account only the errors coming from C-UCPs involving two users, and for very limited channel load values is very close to the simulated p l . In particular, for the PLR approximation of CRA we used equation (22) and equation (18), while for the PLR approximation of ECRA-MRC we used equations (27) and (18), with the numerically evaluated average α. For CRA, when G ≤ 0.3, the approximation approaches the p l simulated performance, while for increasing G the probability of having C-UCPs involving more than two users starts to have an impact on p l and therefore the approximation starts to become loose.…”

“…At the receiver side, SIC is employed for removing interference, once packets are correctly decoded. The excellent performance of E-SSA are shown in [27].…”

Random access schemes for satellite networks, from VSAT to M2M: a survey

“…First, the inclusion of the low‐latency profile in the DVB‐satellite services to handhelds (DVB‐SH) standard has opened up the possibility to add a return link that is complementing the DVB‐SH for interactive services. Consequently, the European Telecommunications Standards Institute (ETSI) S‐MIM standard has adopted the E‐SSA protocol for the asynchronous access to support satellite mobile messaging and low‐data rate services . The technology maturity of E‐SSA is very high, because several joint ESA/Eutelsat activities related to the design and implementation of the DVB‐SH/S‐MIM standards have fostered the deployment of prototypes and supported extensive validation campaigns in the field .…”