where IRS is intelligent reflective surfaces.
An IRS is a new type of relay, with specific characteristics, benefits, and drawbacks. This is discussed in our recent magazine article: https://arxiv.org/pdf/2006.03377.pdf
Very interesting.
Many thanks Prof. Emil Björnson, An interesting paper by Prof. Emil Björnson et al proved that energy efficiency is better in relaying than the IRS.
"Intelligent Reflecting Surface vs. Decode-and-Forward: How Large Surfaces Are Needed to Beat Relaying?"
I think the answer of Prof. Emil Björnson is fully sufficient.
IRS is configured to operate as an anomalous relay. It has the capability to optimize the propagation environment (in real time) between the transmitter and receiver, just like a relaying system. However, IRS offers a potential advantage in terms of reduced hardware complexity at the price of requiring a larger surface. This large surface can be implemented with reduced energy consumption. As IRS has passive characteristics so it ensures that an IRS possesses much lower deployment cost in contrast with the active relaying systems. It can also outperform traditional relaying systems in terms of data rate. Apart from the conceptually appealing superiorities of IRS, it also has some drawbacks such as reduced signal range due to the lack of amplification. You can read about more differences and similarities in these articles. Article Reconfigurable Intelligent Surfaces vs. Relaying: Difference...
Article Towards intelligent reflecting surface empowered 6G terahert...
1) While relays are active in nature ...IRS are mostly passive...
2)relays have different complexity depending whether you using af or df where as IRS have low complex circuitry as they just re-transmit...they do not amplify or decode.
3) we can’t really say which one is better irs or relay as SNR in IRS increases as the no. of elements increase. So it can be lower or higher than relay
IRS (Intelligent Reflective Surface) is typically a new technology that aids in wireless communication where an array of reflective surfaces are used and modified accordingly to direct the propagation of the signal wave towards a specific user/users/receiver. Whereas Relaying is done to pass information from one source to another with the help of a secondary source.
You can read this article, which has discussed the differences and similarities between relays and IRS in detail.
Article Reconfigurable Intelligent Surfaces vs. Relaying: Difference...
Another paper that discusses the difference between relays and RISs in terms of performance is the following.
Article Performance Analysis of Reconfigurable Intelligent Surface-A...
Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming
Qingqing Wu; Rui Zhang
Abstract:
Intelligent reflecting surface (IRS) is a revolutionary and transformative technology for achieving spectrum and energy efficient wireless communication cost-effectively in the future. Specifically, an IRS consists of a large number of low-cost passive elements each being able to reflect the incident signal independently with an adjustable phase shift so as to collaboratively achieve three-dimensional (3D) passive beamforming without the need of any transmit radio-frequency (RF) chains. In this paper, we study an IRS-aided single-cell wireless system where one IRS is deployed to assist in the communications between a multi-antenna access point (AP) and multiple single-antenna users. We formulate and solve new problems to minimize the total transmit power at the AP by jointly optimizing the transmit beamforming by active antenna array at the AP and reflect beamforming by passive phase shifters at the IRS, subject to users' individual signal-to-interference-plus-noise ratio (SINR) constraints. Moreover, we analyze the asymptotic performance of IRS's passive beamforming with infinitely large number of reflecting elements and compare it to that of the traditional active beamforming/relaying. Simulation results demonstrate that an IRS-aided MIMO system can achieve the same rate performance as a benchmark massive MIMO system without using IRS, but with significantly reduced active antennas/RF chains. We also draw useful insights into optimally deploying IRS in future wireless systems.
https://ieeexplore.ieee.org/abstract/document/8811733
https://arxiv.org/pdf/1810.03961.pdf
I think that Intelligent reflective surface (IRC) is a spatial type of relay-based network. Please have a look at this recent paper (https://arxiv.org/pdf/2006.03377.pdf), which might help.
BTW, this technology is expected to be part of future 6G wireless communication networks, so it is considered a hot research topic. Please have a look at my recent paper (6G Wireless Communications Networks: A Comprehensive Survey) for further information. I hope this helps.
https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9598915
Reconfigurable Intelligent Surfaces (RIS/IRS) research area has received too much hype by academia (theoreticians), but very little attention from Industry and telecom companies around the world (except for ZTE, which is doing something not really exactly IRS, but they call it IRS to benefit from the insane hype going on in order to market and promote their products).
My humble thought on this is that Reconfigurable Intelligent Surfaces (RIS/IRS) didn't get the attention and interest of the industry because most of the research conducted on Reconfigurable Intelligent Surfaces (RIS/IRS) is built on top of many impractical assumptions. So, it is better to stay away from this shiny domain and instead try to find something more useful and practical in real life.