Enhancing data persistence of wireless networks: Where NeMo meets OFDM

Network modulation (NeMo)-aided OFDM incremental relay systems

“…In order to integrate the frequency selectivity of OFDM system to the incremental relay, let us utilize NeMo scheme here [16]. Suppose that N OFDM subcarriers are divided into G groups as evenly as possible, and NeMo modulator can be applied for modulated symbols in each group independently [16].…”

“…Suppose that N OFDM subcarriers are divided into G groups as evenly as possible, and NeMo modulator can be applied for modulated symbols in each group independently [16]. Here, the number of subcarriers for each group can be calculated as M = N/G.…”

“…It can be guaranteed that s g will be uniquely identified from x g [19], [20] even though M < D, which corresponds to the ill-posed equation. In Table I, we list the design of ↵ m with some commonly used values of D. Remark that the NeMo modulations help to obtain the benefits from frequency selectivity by distributing multiple symbols into multiple subcarriers [16]. Fig.…”

“…The NeMo for the source S is pretty similar to NeMo-OFDM [16] except the size of NeMo modulator is changed for each phase depending on the number of failed subcarriers in the group. Without the loss of generosity, let us assume D = M for all the groups at the first phase.…”

“…Network modulation (NeMo) is firstly introduced in [15] which enhances successful data persistence by adopting an algebraic way to "combine" symbols which increases the information in a symbol while still guaranteeing the decodability at the sink. Then, NeMo method is applied to wireless communication systems, especially OFDM system which exploits multipath diversity with the aid of multiple subcarriers in order to enhance the error performance at the sink [16]. Now, we further extend and enjoy the advantages of NeMo technique in OFDM-based incremental relaying schemes.…”