ZTE Communications ›› 2021, Vol. 19 ›› Issue (4): 3-15.DOI: 10.12142/ZTECOM.202104002
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ZHANG Zhengquan1,2(), LIU Heng1, WANG Qianli1, FAN Pingzhi1
Received:
2021-10-18
Online:
2021-12-25
Published:
2022-01-04
About author:
ZHANG Zhengquan (Supported by:
ZHANG Zhengquan, LIU Heng, WANG Qianli, FAN Pingzhi. A Survey on Low Complexity Detectors for OTFS Systems[J]. ZTE Communications, 2021, 19(4): 3-15.
Figure 2 OTFS detector structures: (a) DD-domain non-iterative OTFS detector; (b) DD-domain iterative OTFS detector; (c) non-iterative joint TF- and DD-domain OTFS detector; (d) joint non-iterative TF-domain and iterative DD-domain OTFS detector; (e) iterative joint time- and DD-domain OTFS detector; (f) iterative joint TF- and DD-main OTFS detector; (g) iterative joint time-, TF- and DD-main OTFS detector; (h) learning-enabled OTFS detector
Figure 3 OTFS detector classifications: (a) non-iterative and iterative OTFS detectors; (b) single domain and multi-domain OTFS detectors; (c) conventional and learning-based OTFS detectors
Ref. | Detector Structure | Detector Structure Type | Domain | Basic Idea | Advantage | Disadvantage |
---|---|---|---|---|---|---|
Refs. [ | Single- domain OTFS detector | DD-domain non-iterative OTFS detection | DD domain | Adopting non-iterative detection algorithms (e.g., MMSE/ZF) in DD domain | Signal detection is only performed in DD domain; Non-iterative signal detection algorithms are relatively low complexity. | Non-iterative signal detection algorithms suffer from some performance loss. |
Refs. [ | DD-domain iterative OTFS detection | DD domain | Adopting iterative detection algorithms, like MP/AMP and MRC etc., in DD domain | Iterative detection algorithms can achieve better performance. | Iterative detection will increase the complexity of algorithm design; the convergence of algorithms should be analyzed and ensured. | |
Ref. [ | Joint multi- domain OTFS detector | Non-iterative joint TF- and DD-domain OTFS detection | TF domain and DD domain | Joint TF- and DD- domain processing with non-iterative detection algorithms | Joint multi-dimension processing can achieve better detection performance; Joint multi-dimension processing can relax the processing requirements in DD domain. | Joint multi-dimension processing increases the complexity of designing OTFS detector. |
Refs. [ | Joint non-iterative TF-domain and iterative DD-domain OTFS detection | TF domain and DD domain | Employing TF MMSE equalizer to provide good initials for DD-domain iterative MRC detector | Introducing non-iterative TF MMSE equalizer can accelerate the convergence of DD-domain iterative MRC detector; iterative MRC detector can fully merge separable taps to obtain better performance. | TF detection is needed to provide initial estimates; iteration processing increases the complexity; need to add null symbols to construct full channel matrix. | |
Ref. [ | Iterative joint time- and DD-domain OTFS detection | Time domain and DD domain | Joint processing of time and DD domains to form a large iterative detection loop. | Iterative joint time- and DD-domain detection can achieve better performance and faster convergence by fully utilizing time- and DD-domain information. | Iterative joint time- and DD-domain detection increases the complexity of designing OTFS detector; a large amount external information exchange is inevitable. | |
Iterative joint TF- and DD-main OTFS detection | TF domain and DD domain | Joint TF and DD domains that form a large iterative detection loop. | Iterative joint TF- and DD-domain detection can achieve better performance and faster convergence by fully utilizing TF- and DD-domain information. | Iterative joint TF- and DD-domain detection increases the complexity of designing OTFS detector; a large amount external information exchange is inevitable. | ||
Refs. [ | Learning-based OTFS detection | DD domain | Using machine learning techniques to perform signal detection in DD domain or estimate some parameters in conventional OTFS detector. | It is relatively simple to design learning-based signal detection as a black box without understanding expert knowledge of OTFS detection; better detection performance is achieved. | Learning-based detection is un-explainable; more computing capability is required; massive training and testing datasets are necessary. |
Table 1 Summary of OTFS detector structures
Ref. | Detector Structure | Detector Structure Type | Domain | Basic Idea | Advantage | Disadvantage |
---|---|---|---|---|---|---|
Refs. [ | Single- domain OTFS detector | DD-domain non-iterative OTFS detection | DD domain | Adopting non-iterative detection algorithms (e.g., MMSE/ZF) in DD domain | Signal detection is only performed in DD domain; Non-iterative signal detection algorithms are relatively low complexity. | Non-iterative signal detection algorithms suffer from some performance loss. |
Refs. [ | DD-domain iterative OTFS detection | DD domain | Adopting iterative detection algorithms, like MP/AMP and MRC etc., in DD domain | Iterative detection algorithms can achieve better performance. | Iterative detection will increase the complexity of algorithm design; the convergence of algorithms should be analyzed and ensured. | |
Ref. [ | Joint multi- domain OTFS detector | Non-iterative joint TF- and DD-domain OTFS detection | TF domain and DD domain | Joint TF- and DD- domain processing with non-iterative detection algorithms | Joint multi-dimension processing can achieve better detection performance; Joint multi-dimension processing can relax the processing requirements in DD domain. | Joint multi-dimension processing increases the complexity of designing OTFS detector. |
Refs. [ | Joint non-iterative TF-domain and iterative DD-domain OTFS detection | TF domain and DD domain | Employing TF MMSE equalizer to provide good initials for DD-domain iterative MRC detector | Introducing non-iterative TF MMSE equalizer can accelerate the convergence of DD-domain iterative MRC detector; iterative MRC detector can fully merge separable taps to obtain better performance. | TF detection is needed to provide initial estimates; iteration processing increases the complexity; need to add null symbols to construct full channel matrix. | |
Ref. [ | Iterative joint time- and DD-domain OTFS detection | Time domain and DD domain | Joint processing of time and DD domains to form a large iterative detection loop. | Iterative joint time- and DD-domain detection can achieve better performance and faster convergence by fully utilizing time- and DD-domain information. | Iterative joint time- and DD-domain detection increases the complexity of designing OTFS detector; a large amount external information exchange is inevitable. | |
Iterative joint TF- and DD-main OTFS detection | TF domain and DD domain | Joint TF and DD domains that form a large iterative detection loop. | Iterative joint TF- and DD-domain detection can achieve better performance and faster convergence by fully utilizing TF- and DD-domain information. | Iterative joint TF- and DD-domain detection increases the complexity of designing OTFS detector; a large amount external information exchange is inevitable. | ||
Refs. [ | Learning-based OTFS detection | DD domain | Using machine learning techniques to perform signal detection in DD domain or estimate some parameters in conventional OTFS detector. | It is relatively simple to design learning-based signal detection as a black box without understanding expert knowledge of OTFS detection; better detection performance is achieved. | Learning-based detection is un-explainable; more computing capability is required; massive training and testing datasets are necessary. |
Reference | Detection Algorithm | Algorithm Characteristic | Computational Complexity | Performance |
---|---|---|---|---|
Ref. [ | Classical MMSE | Non-iterative | UAMP>EP>AEP >MRC-rake >VB >MP >Classical MMSE ≥low complexity MMSE | |
Ref. [ | Low complexity MMSE | Non-iterative | ||
Ref. [ | lower-upper factorization -based MMSE | Non-iterative | ||
Refs. [ | MP | Iterative | ||
Ref. [ | MF-MP-PC | Iterative | ||
Ref. [ | GAMP | Iterative | ||
Ref. [ | UAMP | Iterative | ||
Ref. [ | ICMP | Iterative | ||
Refs. [ | MRC-rake | Iterative | ||
Ref. [ | EP | Iterative | ||
AEP | Iterative | |||
Ref. [ | VB | Iterative |
Table 2 Summary of computational complexity and performance
Reference | Detection Algorithm | Algorithm Characteristic | Computational Complexity | Performance |
---|---|---|---|---|
Ref. [ | Classical MMSE | Non-iterative | UAMP>EP>AEP >MRC-rake >VB >MP >Classical MMSE ≥low complexity MMSE | |
Ref. [ | Low complexity MMSE | Non-iterative | ||
Ref. [ | lower-upper factorization -based MMSE | Non-iterative | ||
Refs. [ | MP | Iterative | ||
Ref. [ | MF-MP-PC | Iterative | ||
Ref. [ | GAMP | Iterative | ||
Ref. [ | UAMP | Iterative | ||
Ref. [ | ICMP | Iterative | ||
Refs. [ | MRC-rake | Iterative | ||
Ref. [ | EP | Iterative | ||
AEP | Iterative | |||
Ref. [ | VB | Iterative |
Figure 9 Multiple access schemes for downlink hybrid OFDM-OTFS systems in multi-user scenario: (a) hybrid orthogonal frequency division multiple access (OFDMA) and orthogonal time frequency space multiple access (OTFSMA) in both DD and TF domains; (b) hybrid OFDMA and OTFSMA with overlap in the TF domain
Figure 10 BLER performance: (a) two-user orthogonal time frequency space (OTFS) systems without inter-user interference (IUI); (b) two-user hybrid OTFS-orthogonal frequency division multiplexing (OFDM) systems
1 | ITU-R. Framework and overall objectives of the future development of IMT for 2020 and beyond: ITU-R M.2083-0 [R]. 2015 |
2 | 3GPP. Study on NR vehicle-to-everything (V2X) (Release 16): 3GPP TR 38.885 [R]. 2019 |
3 |
CHEN S Z, HU J L, SHI Y, et al. Vehicle-to-everything (v2x) services supported by LTE-based systems and 5G [J]. IEEE communications standards magazine, 2017, 1(2): 70–76. DOI: 10.1109/MCOMSTD.2017.1700015
DOI |
4 | 3GPP. Mobile communication system for railways (Release 17): 3GPP TS 22.289 [S]. 2019 |
5 |
AI B, GUAN K, RUPP M, et al. Future railway services-oriented mobile communications network [J]. IEEE communications magazine, 2015, 53(10): 78–85. DOI: 10.1109/MCOM.2015.7295467
DOI |
6 |
ZHANG Z Q, XIAO Y, MA Z, et al. 6G wireless networks: vision, requirements, architecture, and key technologies [J]. IEEE vehicular technology magazine, 2019, 14(3): 28–41. DOI: 10.1109/MVT.2019.2921208
DOI |
7 |
FAN P Z, ZHAO J, I C L. 5G high mobility wireless communications: challenges and solutions [J]. China communications, 2016, 13 (): 1–13. DOI: 10.1109/CC.2016.7833456
DOI |
8 |
HADANI R, RAKIB S, TSATSANIS M, et al. Orthogonal time frequency space modulation [C]//IEEE Wireless Communications and Networking Conference (WCNC). San Francisco, USA: IEEE, 2017: 1–6. DOI: 10.1109/WCNC.2017.7925924
DOI |
9 |
WEI Z Q, YUAN W J, LI S Y, et al. Orthogonal time-frequency space modulation: a promising next-generation waveform [J]. IEEE wireless communications, 2021, 28(4): 136–144. DOI: 10.1109/MWC.001.2000408
DOI |
10 | 3GPP TSG RA WG1. Overview of OTFS waveform for next generation RAT: Meeting #84-bis R1162929 [R]. Busan, South Korea: 3GPP, 2016 |
11 | 3GPP TSG RA WG1. OTFS modulation waveform and reference signals for new RAT: Meeting #84-bis R1162930 [R]. Busan, South Korea: 3GPP, 2016 |
12 | 3GPP TSG RA WG1. Performance results for OTFS modulation: Meeting #85 R1165620 [R]. Nanjing, China: 3GPP, 2016 |
13 | MobileChina. White paper on 2030+ technology trends [R]. 2019 |
14 |
JING L Y, WANG H, HE C B, et al. Two dimensional adaptive multichannel decision feedback equalization for OTFS system [J]. IEEE communications letters, 2021, 25(3): 840–844. DOI: 10.1109/LCOMM.2020.3039982
DOI |
15 |
THAJ T, VITERBO E. Low complexity iterative rake detector for orthogonal time frequency space modulation [C]//IEEE Wireless Communications and Networking Conference (WCNC). Seoul, Korea (South): IEEE, 2020: 1–6. DOI: 10.1109/WCNC45663.2020.9120526
DOI |
16 |
THAJ T, VITERBO E. Low complexity iterative rake decision feedback equalizer for zero-padded OTFS systems [J]. IEEE transactions on vehicular technology, 2020, 69(12): 15606–15622. DOI: 10.1109/TVT.2020.3044276
DOI |
17 |
JIN C X, BIE Z S, LIN X H, et al. A simple two-stage equalizer for OTFS with rectangular windows [J]. IEEE communications letters, 2021, 25(4): 1158–1162. DOI: 10.1109/LCOMM.2020.3043841
DOI |
18 |
LI S Y, YUAN W J, WEI Z Q, et al. Cross domain iterative detection for orthogonal time frequency space modulation [J]. IEEE transactions on wireless communications, early access. DOI: 10.1109/TWC.2021.3110125
DOI |
19 |
SHAN Y R, WANG F G. Low-complexity and low-overhead receiver for OTFS via large-scale antenna array [J]. IEEE transactions on vehicular technology, 2021, 70(6): 5703–5718. DOI: 10.1109/TVT.2021.3072667
DOI |
20 |
XU X K, ZHAO M M, LEI M, et al. A damped GAMP detection algorithm for OTFS system based on deep learning [C]//IEEE 92nd Vehicular Technology Conference (VTC2020-Fall). Victoria, Canada: IEEE, 2020: 1–5. DOI: 10.1109/VTC2020-Fall49728.2020.9348493
DOI |
21 |
ENKU Y K, BAI B M, WAN F, et al. Two-dimensional convolutional neural network based signal detection for OTFS systems [J]. IEEE wireless communications letters, 10(11): 2514–2518. DOI: 10.1109/LWC.2021.3106039
DOI |
22 |
NAIKOTI A, CHOCKALINGAM A. Low-complexity delay-doppler symbol DNN for OTFS signal detection [C]//IEEE 93rd Vehicular Technology Conference (VTC2021-Spring). Helsinki, Finland: IEEE, 2021: 1–6. DOI: 10.1109/VTC2021-Spring51267.2021.9448630
DOI |
23 | ZHOU Z, LIU L J, XU J R, et al. Learning to equalize OTFS [EB/OL]. (2021-07-17)[2021-08-31]. |
24 |
PANDEY B C, MOHAMMED S K, RAVITEJA P, et al. Low complexity precoding and detection in multi-user massive MIMO OTFS downlink [J]. IEEE transactions on vehicular technology, 2021, 70(5): 4389–4405. DOI: 10.1109/TVT.2021.3061694
DOI |
25 |
TIWARI S, DAS S S, RANGAMGARI V. Low complexity LMMSE Receiver for OTFS [J]. IEEE communications letters, 2019, 23(12): 2205–2209. DOI: 10.1109/LCOMM.2019.2945564
DOI |
26 |
PFADLER A, JUNG P, SZOLLMANN T, et al. Pulse-shaped OTFS over doubly-dispersive channels: one-tap vs. full LMMSE equalizers [C]//IEEE International Conference on Communications Workshops (ICC Workshops). Montreal, Canada: IEEE, 2021: 1–6. DOI: 10.1109/ICCWorkshops50388.2021.9473535
DOI |
27 |
SURABHI G D, CHOCKALINGAM A. Low-complexity linear equalization for OTFS modulation [J]. IEEE communications letters, 2020, 24(2): 330–334. DOI: 10.1109/LCOMM.2019.2956709
DOI |
28 |
SINGH P, MISHRA H B, BUDHIRAJA R. Low-complexity linear MIMO-OTFS receivers [C]//IEEE International Conference on Communications Workshops (ICC Workshops). Montreal, Canada: IEEE, 2021: 1–6. DOI: 10.1109/ICCWorkshops50388.2021.9473839
DOI |
29 |
ZOU T T, XU W J, GAO H, et al. Low-complexity linear equalization for OTFS systems with rectangular waveforms [C]//IEEE International Conference on Communications Workshops (ICC Workshops). Montreal, Canada: IEEE, 2021: 1–6. DOI: 10.1109/ICCWorkshops50388.2021.9473771
DOI |
30 |
KOLLENGODE RAMACHANDRAN M, CHOCKALINGAM A. MIMO-OTFS in high-doppler fading channels: signal detection and channel estimation [C]//IEEE Global Communications Conference (GLOBECOM). Abu Dhabi, United Arab Emirates: IEEE, 2018: 206–212. DOI: 10.1109/GLOCOM.2018.8647394
DOI |
31 |
RAVITEJA P, PHAN K T, JIN Q Y, et al. Low-complexity iterative detection for orthogonal time frequency space modulation [C]//IEEE Wireless Communications and Networking Conference (WCNC). Barcelona, Spain: IEEE, 2018: 1–6. DOI: 10.1109/WCNC.2018.8377159
DOI |
32 |
RAVITEJA P, PHAN K T, HONG Y, et al. Interference cancellation and iterative detection for orthogonal time frequency space modulation [J]. IEEE transactions on wireless communications, 2018, 17(10): 6501–6515. DOI: 10.1109/TWC.2018.2860011
DOI |
33 |
ZHANG H J, ZHANG T T. A low-complexity message passing detector for OTFS modulation with probability clipping [J]. IEEE wireless communications letters, 2021, 10(6): 1271–1275. DOI: 10.1109/LWC.2021.3063904
DOI |
34 |
XIANG L P, LIU Y S, YANG L L, et al. Gaussian approximate message passing detection of orthogonal time frequency space modulation [J]. IEEE transactions on vehicular technology, 2021, 70(10): 10999–11004. DOI: 10.1109/TVT.2021.3102673
DOI |
35 |
YUAN Z D, LIU F, YUAN W J, et al. Iterative detection for orthogonal time frequency space modulation with unitary approximate message passing [J]. IEEE transactions on wireless communications, early access. DOI: 10.1109/TWC.2021.3097173
DOI |
36 |
GE Y, DENG Q W, CHING P C, et al. Receiver design for OTFS with a fractionally spaced sampling approach [J]. IEEE transactions on wireless communications, 2021, 20(7): 4072–4086. DOI: 10.1109/TWC.2021.3055585
DOI |
37 |
CHENG J Q, JIA C L, GAO H, et al. OTFS based receiver scheme with multi-antennas in high-mobility V2X systems [C]//IEEE International Conference on Communications Workshops (ICC Workshops). Dublin, Ireland: IEEE, 2020: 1–6. DOI: 10.1109/ICCWorkshops49005.2020.9145313
DOI |
38 |
LI S Y, YUAN W J, WEI Z Q, et al. Hybrid MAP and PIC detection for OTFS modulation [J]. IEEE transactions on vehicular technology, 2021, 70(7): 7193–7198. DOI: 10.1109/TVT.2021.3083181
DOI |
39 |
LI H, DONG Y Y, GONG C H, et al. Low complexity receiver via expectation propagation for OTFS modulation [J]. IEEE communications letters, 2021, 25(10): 3180–3184. DOI: 10.1109/LCOMM.2021.3101827
DOI |
40 |
YUAN W J, WEI Z Q, YUAN J H, et al. A simple variational Bayes detector for orthogonal time frequency space (OTFS) modulation [J]. IEEE transactions on vehicular technology, 2020, 69(7): 7976–7980. DOI: 10.1109/TVT.2020.2991443
DOI |
41 |
QU H Y, LIU G H, ZHANG L, et al. Low-complexity symbol detection and interference cancellation for OTFS system [J]. IEEE transactions on communications, 2021, 69(3): 1524–1537. DOI: 10.1109/TCOMM.2020.3043007
DOI |
42 |
THAJ T, VITERBO E. Low-complexity linear diversity-combining detector for MIMO-OTFS [J]. IEEE wireless communications letters, 2021, early access. DOI: 10.1109/LWC.2021.3125986
DOI |
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