In addition to the multi-antenna diversity, user cooperation can also be exploited to enhance the security of wireless transmission.
We then determine in Section 'Space diversity by cooperation' the relation between the diversity order d and the set { n u r, u r = 1, …, m r }, for any linear binary JNCC expressed as in Equations (6) and (7).
While this is not the first study to emphasize the importance of diversity on cooperation, we adopt a different approach in which it is neither predetermined nor exogenous.
At the theoretical level, this finding adds to the existing and growing research on the impact of diversity on cooperation [23] [25], and more generally on evolutionary games on graphs [30].
With 2-allele matching and x > 0 (i.e. dissimilar-type matings produce more surviving offspring; Figure 2B), negative frequency-dependent selection arose at the recognition locus because individuals with rare recognition alleles produce an additional x offspring more often, which in some cases maintained maximal values of cue diversity and cooperation.
Comparing Figures 2A and 2C, one can see that 1-allele matching coupled with disassortative mating creates a parameter space under which fairly high (green) values of cue diversity and cooperation can persist even when x = 0, which is not true of 2-allele matching.
Furthermore, the use of interblock precoding, as compared to intrablock precoding, reduces the number of time slots required by the cooperative OFDM system to achieve the maximum diversity induced by cooperation.
Cooperative networking is a modern approach that aims at increasing spatial diversity via user cooperation.
This paradigm requires a critical mass of participation, commitment for trust, diversity, sharing and cooperation.
The cooperation diversity and power allocation with optimal relay selection was considered in [22 25].
