As known, the data rate of the navigation message in current GPS is 50 bps while the bandwidth used for the proposed MC code is 1.024 MHz.
The considered generic application characteristic resembles a bounded logarithmic relation between perceived quality and data rate as illustrated in Figure 5, described by the MOS as a function of the data rate of user (4a).
Using the concept of a protected reference user, we formulate optimization problem (1) as the weighted sum of the data rate of users attached to cell c, or primary users, denoted as R c and the data rate of victim users attached to one neighboring cell, denoted as R vc.
As R n (P n ) is concave in P n for the multi-user case (see Section 4-B1), R n (P n )/P n is maximized when P n → 0 or equivalently R n (P n ) → 0. Reducing P n, and the corresponding R n (P n ), results in a decrease of ∑m ≠ nP m J m /R m as the data rates of the other users are increased because less crosstalk is radiated to them.
The performance of the OCDMA systems is governed by numerous quantitative parameters such as the data rate, simultaneous number of users, the powers of transmitter and receiver, and the type of codes.
Denoting R m,n as the achievable data rate of the mth interrupted SU on the nth subchannel, according to Shannon formula [17], we can obtain: {R_{m,n}} = {B_{n}}{log_{2}}left(1 + frac{{{P_{m,n}}h_{m,n}^{2}}}{{{sigma^{2}}}}right) (17).
Denote C as the achievable data rate of the CRN when it operates in the absence of PU, and the value of C is assumed to be [18] C = B log 2 1 + SNR s (10).
As the data rate increases, the ISI of OTR system becomes more severe and it degrades system performance and capacity.
Note that as the data rate decreases, the number of symbols involved in features' computations also decreases for fixed values of Ns and fs.
As the data rate goes up, the ISI of OTR system becomes more severe and it degrades system performance more than background noise.
