MISO broadcast channels with confidential messages and alternating CSIT

Abstract

Abstract-We study the two-user multiple-input single-output (MISO) broadcast channel with confidential messages under the assumption of alternating channel state information at the transmitter (CSIT). We consider two alternating states: PD and DP which occur for an equal fraction of time. In state PD, the CSIT of the channel to the first receiver is available perfectly without delay (P) while that of the second receiver is available with a delay of one channel use (D); in state DP, the roles of the receivers are reversed. We characterize the exact secure degrees of freedom (s.d.o.f.) region of this system, and show as a corollary that the sum s.d.o.f. is

On SDoF of Multi-Receiver Wiretap Channel With Alternating CSIT

“…Specializing the results in this work to the model studied in [26] reveals that the encoding scheme in [26] outperforms the scheme that we developed in [1] (SDoF of 3/2 vs. 4/3). However, the outer bound that we have established in this work is more general; and, it subsumes the outer bound in [26] and the one developed in the context of broadcast channel with delayed CSIT in [21]. Recently, in [27] the authors extended their model in [26] to a more general setup in which the two receivers are allowed to convey either perfect (P), delayed (D) or no CSIT (N) and characterized the full SDoF region.…”

“…We now highlight the key differences between some of the results in this paper and a similar work which was independently done in parallel in [26]. In [26], the authors studied a MISO broadcast channel with confidential messages in which the transmitter is allowed to alternate between two states, i.e., PD and DP, equal fractions of communication time.…”

“…In [26], the authors studied a MISO broadcast channel with confidential messages in which the transmitter is allowed to alternate between two states, i.e., PD and DP, equal fractions of communication time. The authors characterize the complete SDoF region.…”

“…The authors characterize the complete SDoF region. As opposed to the model in [26], the model that we study in this paper as shown in Figure 2 is more general, since it allows more leverage to the transmitter to choose between four possible states, i.e., PP, PD, DP, and DD. Specializing the results in this work to the model studied in [26] reveals that the encoding scheme in [26] outperforms the scheme that we developed in [1] (SDoF of 3/2 vs. 4/3).…”

“…As opposed to the model in [26], the model that we study in this paper as shown in Figure 2 is more general, since it allows more leverage to the transmitter to choose between four possible states, i.e., PP, PD, DP, and DD. Specializing the results in this work to the model studied in [26] reveals that the encoding scheme in [26] outperforms the scheme that we developed in [1] (SDoF of 3/2 vs. 4/3). However, the outer bound that we have established in this work is more general; and, it subsumes the outer bound in [26] and the one developed in the context of broadcast channel with delayed CSIT in [21].…”