8 show the optimal nodes deployment for SISO, DSTBC based CMISO and CB based CMISO transmissions, respectively.
Table 4 shows energy efficiency of CB based CMISO transmission vs DSTBC based CMISO transmission, the energy efficiency is defined as [E.
In order to reduce the energy consumption,the nodes deployment for multi-hop SISO, multi-hop DSTBC based CMISO, multi-hop CB based CMISO transmissions are optimized.
System description of a DSTBC UWB system is introduced in Section 2.
We consider a DSTBC system, which is equipped with Q (Q [greater than or equal to] 1) receive antennas.
Then, the coded bits are interleaved and fed into the DSTBC encoder.
In this section, an SISO MSD mathematical model will be derived for the DSTBC UWB systems.
In the following, an MSD metric will be presented for the DSTBC UWB systems.
Remark 2: The mathematical model for MSD metric has been analyzed in DSTBC UWB systems.
The differential modulation can be represented by a DSTBC trellis structure , which is shown in Fig.
k]) can be calculated through the forward and backward recursions based on the DSTBC trellis structure.
During the iterative decoding process, the inputs to DSTBC detector are a priori or the extrinsic information of the input symbols, which will be delivered to channel decoder; the decoder computes the APP from (30), and then sends back to the detector as a priori information for the next iteration [22-24].