## 6 Evaluation Results
Thus, the transceiver's energy consumption per second in sleep mode can be calculated from \(E_{b\_Analog\_Rx}\) (energy consumption by receiver circuits of the RF section per bit per node), which is found to be \(-34.8161\) dBJ for 16-DQPSK, 16-QAM, 16-QQPSK, 16-FOFDM, and BPSK-16 FOFDM, and \(-36.3601\) dBJ for 16-WOFDM and BPSK-16 WOFDM. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{_Modulation_} & \multicolumn{3}{c}{**Transmit (T\({}_{\textbf{x}}\)) Mode**} & \multicolumn{3}{c}{**Receive (R\({}_{\textbf{x}}\)) Mode**} \\ \cline{2-9}  & \(E_{\textbf{{Mod}}}\) _per_ & \(E_{b\_Analog\_Tx}\) & \(E_{b\_Total\_Tx}\) _per_ & \(E_{\textbf{{Dem}}}\) _per_ & \(E_{\textbf{{Det}}}\) _per bit_ & \(E_{b\_Analog\_Rx}\) & \(E_{b\_Total\_Rx}\) \\ \multirow{2}{*}{_Type_} & _bit per node_ & _per bit per node_ & _bit per node_ & _per node_ & _per bit per_ & _per bit per_ \\  & _in dBJ_ & _node in dBJ_ & _in dBJ_ & _in dBJ_ & _in dBJ_ & _node in dBJ_ \\ \hline
16-DQPSK & \(-31.7203\) & \(-36.4958\) & \(-30.4720\) & \(-32.1389\) & \(-30.7033\) & \(-58.7955\) & \(-28.3517\) \\
16-QAM & \(-31.2628\) & \(-38.995\) & \(-30.5863\) & \(-31.9686\) & \(-30.7033\) & \(-58.7955\) & \(-28.2797\) \\
16-OQPSK & \(-30.8951\) & \(-55.8558\) & \(-30.8813\) & \(-31.1203\) & \(-30.7033\) & \(-58.7955\) & \(-27.8965\) \\
16-FOFDM & \(-30.0134\) & \(-53.855\) & \(-29.9955\) & \(-30.7192\) & \(-30.7033\) & \(-58.7955\) & \(-27.7009\) \\
16-WOFDM & \(-31.0294\) & \(-56.370999\) & \(-31.0167\) & \(-31.7203\) & \(-30.7033\) & \(-60.3395\) & \(-28.1718\) \\ BPSK-16 FOFDM & \(-29.86\) & \(-58.1958\) & \(-29.8536\) & \(-30.587\) & \(-30.7033\) & \(-58.7955\) & \(-27.6345\) \\ BPSK-16 WOFDM & \(-30.8764\) & \(-60.741\) & \(-30.8719\) & \(-31.2681\) & \(-30.7033\) & \(-60.3395\) & \(-27.9662\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Energy Consumption in Transmit and Receive Modes. The time delays involved during the communication are listed in Table 4. It is observed that \(T_{tr\_MIMO}\) is 1.75 \(\mu\)s/bit for all modulation techniques. \(T_{pr\_MIMO}\) is calculated using Equation (20) for \(d^{L}=10\ m\) and \(d^{L}=100\ m\). It is also observed that the modulator incurred a higher processing time (\(T_{Mod}\)) than the demodulator (\(T_{Dmod}\)). This is because more mathematical operations are involved in modulating the signal than demodulating. The total processing delay \(T_{pc\_MIMO}\) is considerably high as compared to \(T_{tr\_MIMO}\) and \(T_{pr\_MIMO}\) due to lower processing speed of TelosB mote. Thus, \(T_{pc\_MIMO}\) is the most dominant time delay factor for the total time delay of virtual-MIMO (\(T_{V-MIMO}\)). 16-DQPSK based system is found to incur the least total time delay due to its lower \(T_{pc\_MIMO}\) as compared to other six modulation techniques, followed by 16-QAM, 16-WOFDM, BPSK-16 WOFDM, 16-OQPSK, 16-FOFDM, and BPSK-16 FOFDM. \(T_{SISO}\) is lower than \(T_{V-MIMO}\) because no \(T_{Det}\) is involved in the SISO system. From a comparison of the results between Tables 1 and 4, it can be observed that modulation techniques with less \(T_{pc\_MIMO}\) will also exhibit less \(E_{b\_Digital}\) value, and vice versa. For example, the \(T_{pc\_MIMO}\) and \(E_{b\_Digital}\) of 16-DQPSK is 0.2195 s, and \(-31.2591\) dBJ (or 0.7483 \(\times 10^{-3}\) J), respectively, while for BPSK-16 FOFDM, it is 0.2836 s, and \(-29.8167\)dBJ (or 1.0431 \(\times 10^{-3}\) J), respectively. The spectral efficiency can be calculated using Equation (17) for various \(\frac{E_{b}}{N_{o}}\) values. The four data points on each curve are obtained by setting the BER values to \(10^{-1}\), \(10^{-2}\), \(10^{-3}\), and \(10^{-4}\). It can be observed from Equation (17) that by increasing \(\frac{E_{b}}{N_{o}}\), the spectral efficiency will increase.