Different opportunistic transmission techniques were proposed for wireless communication systems. In this work, we explore the opportunistic technique in which the transmissions are made only when the fading is above a threshold. As result, this technique mitigates almost completely the undesirable effects produced by the fading channel.Seeking to potentialize the performance of the aforementioned opportunistic technique and aiming to analyze it in different scenarios, in this work different hybrid schemes combining opportunism with other transmission/reception techniques are proposed, modeled and analyzed. In particular, the opportunistic technique is combined with two different diversity schemes. Spatial diversity (or antenna array diversity) with maximal ratio combining (MRC) is firstly considered. Then, by assuming a multiuser scenario, the multiuser diversity technique is also employed with opportunistic transmission.As wireless communication systems typically employ error correcting codes, in this work opportunistic transmission with error correcting codes are employed. Specifically, convolutional codes and trellis coded modulation (TCM) are chosen in the analysis, once closed-form expressions to evaluate the bit error rate (BER) can be obtained.Later, an opportunistic code division multiple access (CDMA) is proposed. Thus, the performance of opportunistic transmission in environments with presence of own-cell interference (or multiple access interference -MAI) and co-cell interference (CCI) are evaluated. Therein, the uplink is analyzed and aspects as the channel reuse factor are considered in the analysis.Finally, by considering the opportunistic cellular system, the cellular spectral efficiency is evaluated. For this, an procedure to calculate the cell coverage radius for each modulation scheme is employed, by considering that adaptive modulation is used and that a target mean BER must be guaranteed.In general, BER and the spectral efficiency are performance indicators considered in this work to evaluate the proposed schemes. As result, closed-form expressions are derived and their accuracy are validated by employing Monte Carlos simulations. In the analysis, BPSK, QPSK and M-QAM modulations are considered. Moreover, additive white Gaussian noise (AWGN) and Rayleigh fading are assumed in the channel model.The results show that the derived expressions are highly accurate to model the performance of the proposed schemes. In addition, it is determined that the hybrid schemes improves the performance in relation to opportunistic systems.