Figure 1 Generalized system model composed of a main transmitter, main receiver, and cluster of relaying network elements.
As expected, in the presence of individual channel gains with different average path loss characteristics (i.e., with different long-term signal strength), the variability of the received SNR increases at the main receiver, causing a less abrupt improvement in the sigmoid function of the CDF as the value of γ 0 grows.
Based on the model presented above, the signal that the main receiver experiences (in a spectrum portion with a flat frequency response) at transmission time interval i attains the following (dot product) form: r [ i ] = h [ i ] · x [ i ] + n = h [ i ] · w [ i ] s + n, (1).
The signal can be relayed from the main receiver (ordinarily atop a passenger car) to relay points, or bridges, atop other cars in which service is provided.
The received SNR that the main receiver experiences at transmission time interval i is then given by the following: γ [ i ] = | h [ i ] · w [ i ] | 2 E { | s | 2 } P N = ∑ m = 1 M γ ¯ m [ i ] w m [ i ] e j ψ m [ i ] 2, (2).
Based on the previous formulas, it is possible to show that the BEP that the distributed antenna system provides in the second hop, when the SNR at the main receiver is approximated as a weighted sum of non-central χ 2 distributions with different degrees of freedom, attains the following closed-form expression: P e = ∑ k = 0 ∞ W k ( σ 1, σ 2 ) P e ( k + 1 ), (39).
In other words, the limited feedback information that the main receiver reports is used to establish a DAS in the second hop.
William Novak, an assistant district attorney, described Mr. Guerrero as the "main receiver" of the drug shipments sent as freight and the mastermind of the smuggling ring.
Since it is assumed that the bottleneck of the system lies in the second hop, end-to-end performance can be improved, implementing a coherent transmission scheme from the cluster of RSs to the main receiver (i.e., adjusting the phases of the channel gains that the main receiver observes from each of the antenna elements that surrounds the main transmitter).
