# A New Intra-Cluster Scheduling Scheme for Real-Time Flows in Wireless Sensor Networks
## 2 Proposed Scheme
### Procedure of the Proposed Scheme
Thus, cluster H1 can utilize the IntraRecv time slots for IntraSend scheduling and schedule the transmission _j_\(\rightarrow\)_c_ of \(F1\) and _h_\(\rightarrow\)_H_2 of \(F5\) in the same slot #4 due to non-interference. Similarly, cluster H2 schedule transmission i_\(\rightarrow\)_h_ of F2 in slot #1. Transmission _p_\(\rightarrow\)_H_2 of \(F3\) and _e_\(\rightarrow\)_g_ of \(F4\) are also scheduled in slot #1 due to non-interference with high priority flows. Cluster \(H2\) has also outgoing flows. In this, it can utilize the IntraRecv time slots. Therefore, transmission _h_\(\rightarrow\)_H_2 is scheduled in time slot #4. Transmission of F3 is already reached to cluster head so it cannot be schedule in slot #4. Finally, the transmission _g_\(\rightarrow\)_H_2 of \(F4\) is conflicting with transmission _h_\(\rightarrow\)_H_2 of \(F2\), therefore, the transmission _h_\(\rightarrow\)_H_2 is delayed by one slot and schedule in the next time slot #5 as shown in Table 4. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{10}{c}{Previous IntraSend Scheduling} \\ \hline
**Cluster** & **Flow\#** & \(\mathbf{\mathit{r_{i}}}\) & **1** & **5** & **9** & \(\mathbf{\mathit{a_{i}^{SH}}}\) \\ \hline \multirow{3}{*}{H1} & F1 & 0 & a\(\rightarrow\)b & b\(\rightarrow\)H1 & & 5 \\ \cline{2-10}  & F5 & 0 & & j\(\rightarrow\)c & c\(\rightarrow\)H1 & 9 \\ \cline{2-10}  & F2 & 0 & i\(\rightarrow\)h & h\(\rightarrow\)H2 & & 5 \\ \cline{2-10}  & F3 & 0 & p\(\rightarrow\)H2 & & & 1 \\ \cline{2-10}  & F4 & 0 & e\(\rightarrow\)g & & g\(\rightarrow\)H2 & 9 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Results of previous scheme IntraSend scheduling of Figure 2. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multicolumn{10}{c}{Previous InterComm Scheduling} \\ \hline
**Flow\#** & \(\mathbf{\mathit{a_{i}^{SH}}}\) & **2** & **3** & **6** & **7** & **10** & **11** & **14** & **15** & **18** & \(\mathbf{\mathit{a_{i}^{DH}}}\) \\ \hline F1 & 5 & & & & H1\(\rightarrow\)H3 & H3\(\rightarrow\)H5 & & & & & 7 \\ \hline F2 & 5 & & & & H2\(\rightarrow\)H1 & H1\(\rightarrow\)H3 & & & & 11 \\ \hline F3 & 1 & H2\(\rightarrow\)H4 & H4\(\rightarrow\)H5 & & & & & & 3 \\ \hline F4 & 9 & & & & & H2\(\rightarrow\)H4 & H4\(\rightarrow\)H3 & & & 14 \\ \hline F5 & 9 & & & & & & H1\(\rightarrow\)H2 & H2\(\rightarrow\)H4 & 18 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of previous scheme InterComm scheduling of Figure 2. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{10}{c}{Previous IntraRecv Scheduling} \\ \hline
**Cluster** & **Flow\#** & \(\mathbf{\mathit{a_{i}^{DH}}}\) & **4** & **8** & **12** & **16** & **20** & **24** & \(\mathbf{\mathit{a_{i}}}\) \\ \hline \multirow{3}{*}{H5} & F1 & 7 & & H5\(\rightarrow\)m & m\(\rightarrow\)q & & & & 12 \\ \cline{2-10}  & F5 & 18 & & & & & H5\(\rightarrow\)n & n\(\rightarrow\)t & 24 \\ \hline \multirow{3}{*}{H3} & F2 & 11 & & & H3\(\rightarrow\)k & k\(\rightarrow\)l & & & 16 \\ \cline{2-10}  & F4 & 14 & & & & H3\(\rightarrow\)d & & & 16 \\ \hline H4 & F3 & 3 & H4\(\rightarrow\)r & r\(\rightarrow\)o & & & & 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of previous scheme IntraRecv scheduling of Figure 2.  
In InterComm scheduling, the global cluster header schedule the flows from _F1_ to _F5_ from source cluster head to destination head as shown in Table 5.  
IntraSend and IntraRecv scheduling can utilize each other slots but cannot utilize the InterComm time slots due to the high transmission power of the cluster heads. As shown in Table 5, the global cluster head could schedule the flow _F1_ from source cluster-head _H1_ to neighbor the cluster head _H3_. Furthermore, the neighbor cluster-head _H3_ could schedule the data to destination cluster _H5_. Similarly, for the _F2_ flow, the global cluster-head cannot schedule the flow _H2_\(\rightarrow\)_H1_ in the time slot #6 due to the interference of high priority flow _F1_.