The other is the subcarrier index modulation sim, also known as orthogonal frequency division multiplexing ofdmim, wherein the frequency subcarrierindex of the transmitted symbol carries. Each subcarrier is modulated with a conventional digital modulation scheme such as qpsk, 16qam, etc. The indices can be specified for each symbol and transmit antenna. Haas enhanced subcarrier index modulation sim ofdm, proc. Each subblock consists of s n g subcarriers and v out of s are selected to transmit mary data symbols with 1. Orthogonal frequency division multiplexing with index modulation. Institute for digital communications, joint research institute for signal and image. Pdf comparative study of selected subcarrier index modulation. Orthogonal frequencydivision multiplexing wikipedia. Orthogonal frequency division multiplexing with index modulation ofdmim conveys additional information bits via the indices of active subcarriers. Differential subcarrier index modulation ieee journals. Institute for digital communications, joint research.
Determining the subcarrier modulation format ieee 802. In this paper, a differential subcarrier index modulation dsim scheme is proposed, which entirely avoids the need for any channel knowledge at the receiver side. Subcarrierindex modulation ofdm request pdf researchgate. Orthogonal frequency division multiplexing with index modulation ofdm im is a recently developed technique which modulates part of the information bits using the indices of ofdm subcarriers. This acts as a bank of demodulators, translating each carrier down to dc. Ofdm with index modulation for asynchronous mmtc networks. The lowpass equivalent ofdm signal is expressed as. Pdf orthogonal frequency division multiplexing with subcarrier index modulation simofdm is recently proposed to enhance the. In the generalized code index modulation gcim 1416, extra information bits are carried by the selection of spreading codes. Multiplexing method of sharing a bandwidth with other independent data channels.
A new transmission approach, referred to as subcarrierindex modulation sim is proposed to be integrated with the orthogonal frequency division. Ofdm with interleaved subcarrierindex modulation ieee. One of the main challenges in orthogonal frequency division multiplexing ofdmsubcarrier index modulation sim systems is the huge amount of resources required to obtain channel state information at the receiver side. Generalized schemes of orthogonal frequency division. In telecommunications, orthogonal frequencydivision multiplexing ofdm is a type of digital transmission, and a method of encoding digital data on multiple carrier frequencies. The ofdm modulator enables you to specify the subcarrier indices for the pilot signals. Osa the robustness of subcarrierindex modulation in 16. Dynamic differential modulation of subcarriers in ofdm. Performance of ofdm with enhanced subcarrier index modulation using qam international organization of scientific research 42 p a g e to see how ofdm works, it is necessary to look at the receiver. Recently, ofdm has been combined with index modulation ofdmim 1012. Subcarrier spacing in ofdm signal processing stack exchange. Ofdmsubcarrier index selection for enhancing security and. In this letter, a simple and efficient subcarrier level interleaving scheme is introduced to improve the performance of conventional ofdm im through enlarging the euclidean distances among the.
Index termsorthogonal frequencydivision multiplexing with subcarrier number modulation ofdmsnm, subcarrier. The other is the subcarrier index modulation sim, also known as orthogonal frequency division multiplexing ofdm im, wherein the frequency subcarrier index of the transmitted symbol carries. Pdf subcarrierindex modulation aided ofdm will it work. Integration of multiplemode subcarrier index modulation with ofdm written by prof. In this paper, taking a different approach from 3, we propose a novel transmission scheme called ofdm with index modulation ofdmim for frequency selective fading channels.
Enhanced subcarrier index modulation sim ofdm dobroslav tsonev, sinan sinanovic and harald haas institute fordigital communications,joint research institute forsignal and image processing, the university of edinburgh,eh9 3jl, edinburgh,uk email. There is no physical difference between a carrier and a subcarrier. Simulation results the proposed scheme is compared with conventional ofdm with 5 subcarriers as data carrying subcarriers for conventional ofdm. The reason for the large outofband emission of a basic ofdm signal is the use. Achieve almost the same bwe with loworder mqam and better papr performance. Ofdm is a combination of modulation and multiplexing. Extra bits are carried by the indices of active subcarriers to compensate inefficient use of spectrum. Performance analysis of subcarrier index modulationofdm.
In this scheme, the number of active ofdm subcarriers varies according to incoming bit stream and the data is transmitted only on the selected subcarriers. We present in numerical simulations the robustness of subcarrier index modulation sim ofdm to combat laser phase noise. In ofdm gim2,the index modulation is applied independently on in phase and quadrature per sub carrier. Performance of ofdm with enhanced subcarrier index. A radiooverfiber rof system employing subcarrier index modulation sim orthogonal frequencydivision multiplexing ofdm signal is proposed and experimentally demonstrated in this paper. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast. Subcarrier index modulation based flexible ofdm system. Ofdm has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, dsl internet access, wireless networks, power line networks. R fo but windowing possible for single carrier to improve windowing not possible on a subcarrier to exploit implementation. The examples of the med in the bpskaided ofdm and the 4qamaided sim4,1 schemes, where the variance of the apsk symbol. A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. A new transmission approach, referred to as subcarrierindex modulation sim is proposed to be integrated with the orthogonal frequency division multiplexing. Then, a simple yet effective technique based on combinatorial number system is used to map the information bits to the.
Index modulation the main advantage of the mimo ofdmim technique 1 over ofdm is that it selects and maps only the active subcarriers out of the incoming bit streams and applies ifftfft to them to avoid unnecessary computations for any inactive subcarriers. In particular, ofdm with index modulation ofdmim 12 and ofdm with subcarrier number modulation ofdmsnm are among the promising indexbased and numberbased modulation techniques for. Until this time, we needed a large number of subcarrier oscillators to perform parallel modulations and demodulations. In 10,11, the subcarrier im sim concept has been proposed based on a principle reminiscent of the implicit information conveyed by the activated antenna index in spatial modulation sm based multipleinputmultipleoutput mimo systems.
In this scheme, information is conveyed not only by mary signal constellations as in classical ofdm, but. Construct an ofdm modulator that has two symbols and insert a dc null. Subcarrierindex modulation sim orthogonal frequency. Although simofdm has lower spectral efficiency compared to the conventional coofdm system, it is a good candidate for 16qam coofdm system with 1024point. Subcarrierindex modulation sim orthogonal frequencydivision multiplexing ofdm was proposed as the first attempt to extend the gist of sm to the frequency domain in order to solve the aforementioned issues regarding system complexity and device size. The rate field, which is in the signal symbol, contains the data rate information, which is. Mao et al dualmode index modulation aided ofdm figure 1.
In this paper, an enhanced dctofdm with index modulation im edctofdmim is. The proposed scheme uses 5 subcarriers, 4 for data and one subcarrier for side information. Other examples of indexbased modulation systems that involve orthogonal frequencydivision multiplexing ofdm include subcarrierindex. In this work, it is considered n size ofdmim block, where subcarriers are equally split into g subblocks.
Provide the design freedom degree with a flexible range of. A new transmission approach, referred to as subcarrierindex modulation sim is proposed to be integrated with the orthogonal frequency division multiplexing ofdm systems. The other modulation schemes like ook with sim, psk with subcarrier index modulation is discussed here and simulated by using matlab. Ieee transactions on communications 1 a joint code. Orthogonal frequencydivision multiplexing ofdm essentially identical to coded ofdm cofdm is a digital multicarrier modulation scheme, which uses a large number of closelyspaced orthogonal subcarriers. The guard bands provide buffers between consecutive ofdm symbols to protect the integrity of transmitted signals by reducing intersymbol interference. Since ifft is used for modulation the spacing of the subcarriers is such that at the frequency where we evaluate the received signal the center frequency of each subcarrier all other signals are zero. Urmila bhanja published on 20190511 download full article with reference data and citations. Abstract the integration of subcarrier index modulation with multiplemode ofdm and simofdm are discussed in this paper. A lookup table of index modulation for g1 d 2, l d 4, and k d 2. Orthogonal frequency division multiplexing ofdm modulation a mapping of the information on changes in the carrier phase, frequency or amplitude or combination. In this letter, a simple and efficient subcarrierlevel interleaving scheme is introduced to improve the performance of conventional ofdmim through enlarging the euclidean distances among the. Subcarrierindex modulation ofdm ieee conference publication. The idea of ofdm is to spread data across multiple overlapping subcarriers.
Consequently, the determination of the active subcarriers according to the incoming bits arises as. In the proposed edctofdmim scheme, the maximum likelihood ml detector used for symbol bits and index bits recovering. Orthogonal frequency division multiplexing with index modulation contd first, a simple lookup table is implemented to map the incoming information bits to the subcarrier indices and an ml detector is employed at the receiver. Draft 0 enhanced dctofdm system with index modulation. Each sub carrier is modulated with a conventional modulation scheme such as. A requirement for the ofdm subcarrier orthogonality 3. Proposal and demonstration of subcarrier index modulation. Index modulation with papr and beamforming for 5g mimo. Subcarrier index modulation based flexible ofdm system compared with conventional ofdm system, hsbpsksimofdm and double asksim for ofdm. Enhanced subcarrier index modulation sim ofdm request pdf. A major breakthrough in the history of ofdm came in 1971 when weinstein and ebert3 used discrete fourier transform dft to perform baseband modulation and.
As part of this, an investigation of detrimental effects on ofdm is presented, showing the effect of. On the other hand, frequency index modulation fim 17 is an ofdm system based, in this scheme extra bits are carried by the. When there is more than one transmit antenna, ensure that the pilot indices for each symbol differ between antennas. Orthogonal frequency division multiplexing with index.
More specifically, it relates to adding an additional dimension to the conventional twodimensional 2d amplitudephase modulation apm techniques, i. Integration of multiplemode subcarrier index modulation. In the system, the sim will add a new freedom to the conventional modulation techniques i. Compressed sensing improves the performance of subcarrier. Subcarrier index qam, a new hybrid modulation scheme for. As they are orthogonal it is still possible to demodulate them. An enhanced subcarrier index modulation ofdm esimofdm scheme has been proposed in 2 which can operate without requiring excess subcarriers. Pdf equiprobable subcarrier activation method for ofdm. The resulting signal is integrated over the symbol period to regenerate the.
Orthogonal frequency division multiplexing with index modulation ofdmim is a recently developed technique which modulates part of the information bits using the indices of ofdm subcarriers. In particular, ofdm with index modulation ofdm im 12 and ofdm with subcarrier number modulation ofdm snm are among the promising index based and numberbased modulation techniques for. The ability of using dfb lasers with simofdm in 16qam coofdm system with 1024point fft has been verified. That means, all other subcarriers are 0 at the evaluation point of a specific subcarrier. In ofdm gim1, the number of active subcarriers can be varied according to the input bit string. Enhanced orthogonal frequencydivision multiplexing with.
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