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61-527: Nipkow has been called the "father of television", together with other early figures of television history like Karl Ferdinand Braun . The first regular television service in the world, Fernsehsender Paul Nipkow , was named in his honour. Nipkow was born in Lauenburg (now Lębork) in the Prussian province of Pomerania , now part of Poland. While at school in neighbouring Neustadt (now Wejherowo), in

122-523: A crystal detector . Wireless telegraphy claimed Dr. Braun's full attention in 1898, and for many years after that he applied himself almost exclusively to the task of solving its problems. Dr. Braun had written extensively on wireless subjects and was well known through his many contributions to the Electrician and other scientific journals. In 1899, he would apply for the patent Wireless electro transmission of signals over surfaces . Also in 1899, he

183-402: A matrix channel which consists of all N t N r {\displaystyle N_{t}N_{r}} paths between the N t {\displaystyle N_{t}} transmit antennas at the transmitter and N r {\displaystyle N_{r}} receive antennas at the receiver. Then, the receiver gets the received signal vectors by

244-422: A MIMO system (Zheng and Tse, 2003). In particular, achieving high spatial multiplexing gains is of profound importance in modern wireless systems. Given the nature of MIMO, it is not limited to wireless communication. It can be used for wire line communication as well. For example, a new type of DSL technology (gigabit DSL) has been proposed based on binder MIMO channels. An important question which attracts

305-402: A MIMO system is increased as the number of antennas is increased, proportional to the smaller of the number of transmit antennas and the number of receive antennas. This is known as the multiplexing gain and this basic finding in information theory is what led to a spurt of research in this area. Despite the simple propagation models used in the aforementioned seminal works, the multiplexing gain

366-488: A directional signal. This invention led to the development of radar , smart antennas , and MIMO . Braun's British patent on tuning was used by Marconi in many of his tuning patents. Guglielmo Marconi used Braun's patents (among others). Marconi would later admit to Braun himself that he had " borrowed " portions of Braun's work . In 1909, Braun shared the Nobel Prize for physics with Marconi for "contributions to

427-476: A method for increasing capacity using "an array of receiving antennas at the base station" with a "plurality of remote users." Arogyaswami Paulraj and Thomas Kailath proposed an SDMA-based inverse multiplexing technique in 1993. Their US patent (No. 5,345,599 issued in 1994 ) described a method of broadcasting at high data rates by splitting a high-rate signal "into several low-rate signals" to be transmitted from "spatially separated transmitters" and recovered by

488-572: A paper that also suggested it is possible to multiply the capacity of a wireless link using what the author described as "layered space-time architecture." Greg Raleigh, V. K. Jones, and Michael Pollack founded Clarity Wireless in 1996, and built and field-tested a prototype MIMO system. Cisco Systems acquired Clarity Wireless in 1998. Bell Labs built a laboratory prototype demonstrating its V-BLAST (Vertical-Bell Laboratories Layered Space-Time) technology in 1998. Arogyaswami Paulraj founded Iospan Wireless in late 1998 to develop MIMO-OFDM products. Iospan

549-558: A picture into a linear sequence of points. Accounts of its invention state that the idea came to him while sitting alone at home with an oil lamp on Christmas Eve , 1883. Alexander Bain had transmitted images telegraphically in the 1840s but the Nipkow disk improved the encoding process. He applied to the imperial patent office in Berlin for a patent covering an "electric telescope" for the "electric reproduction of illuminating objects", in

610-418: A statistical detection problem, and addressed using a variety of techniques including zero-forcing, successive interference cancellation a.k.a. V-blast , Maximum likelihood estimation and recently, neural network MIMO detection. Such techniques commonly assume that the channel matrix H {\displaystyle \mathbf {H} } is known at the receiver. In practice, in communication systems,

671-472: A task group in late 2003 to develop a wireless LAN standard delivering at least 100 Mbit/s of user data throughput. There were two major competing proposals: TGn Sync was backed by companies including Intel and Philips , and WWiSE was supported by companies including Airgo Networks, Broadcom , and Texas Instruments . Both groups agreed that the 802.11n standard would be based on MIMO-OFDM with 20 MHz and 40 MHz channel options. TGn Sync, WWiSE, and

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732-583: A third proposal (MITMOT, backed by Motorola and Mitsubishi ) were merged to create what was called the Joint Proposal. In 2004, Airgo became the first company to ship MIMO-OFDM products. Qualcomm acquired Airgo Networks in late 2006. The final 802.11n standard supported speeds up to 600 Mbit/s (using four simultaneous data streams) and was published in late 2009. Surendra Babu Mandava and Arogyaswami Paulraj founded Beceem Communications in 2004 to produce MIMO-OFDM chipsets for WiMAX . The company

793-423: Is a fundamental property that can be proved under almost any physical channel propagation model and with practical hardware that is prone to transceiver impairments. A textbook by A. Paulraj, R. Nabar and D. Gore has published an introduction to this area. There are many other principal textbooks available as well. There exists a fundamental tradeoff between transmit diversity and spatial multiplexing gains in

854-446: Is a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation . MIMO has become an essential element of wireless communication standards including IEEE 802.11n (Wi-Fi 4), IEEE 802.11ac (Wi-Fi 5), HSPA+ (3G), WiMAX , and Long Term Evolution (LTE). More recently, MIMO has been applied to power-line communication for three-wire installations as part of

915-410: Is achieved through waterfilling , that is where d 1 , … , d min ( N t , N r ) {\displaystyle d_{1},\ldots ,d_{\min(N_{t},N_{r})}} are the diagonal elements of D {\displaystyle \mathbf {D} } , ( ⋅ ) + {\displaystyle (\cdot )^{+}}

976-424: Is called channel sounding or channel estimation . A known signal is sent to the mobile device that enables it to build a picture of the channel environment. The mobile device sends back the channel characteristics to the transmitter. The transmitter can then apply the correct phase and amplitude adjustments to form a beam directed at the mobile device. This is called a closed-loop MIMO system. For beamforming , it

1037-553: Is limited by the lesser of the number of antennas at the transmitter or receiver. Spatial multiplexing can be used without CSI at the transmitter, but can be combined with precoding if CSI is available. Spatial multiplexing can also be used for simultaneous transmission to multiple receivers, known as space-division multiple access or multi-user MIMO , in which case CSI is required at the transmitter. The scheduling of receivers with different spatial signatures allows good separability. Diversity coding techniques are used when there

1098-458: Is more accurately termed multi-user multiple-input single-output (MU-MISO). MIMO is often traced back to 1970s research papers concerning multi-channel digital transmission systems and interference (crosstalk) between wire pairs in a cable bundle: AR Kaye and DA George (1970), Branderburg and Wyner (1974), and W. van Etten (1975, 1976). Although these are not examples of exploiting multipath propagation to send multiple information streams, some of

1159-403: Is multi-stream beamforming , in the narrowest definition. In more general terms, it is considered to be all spatial processing that occurs at the transmitter. In (single-stream) beamforming, the same signal is emitted from each of the transmit antennas with appropriate phase and gain weighting such that the signal power is maximized at the receiver input. The benefits of beamforming are to increase

1220-434: Is no channel knowledge at the transmitter. In diversity methods, a single stream (unlike multiple streams in spatial multiplexing) is transmitted, but the signal is coded using techniques called space-time coding . The signal is emitted from each of the transmit antennas with full or near orthogonal coding. Diversity coding exploits the independent fading in the multiple antenna links to enhance signal diversity. Because there

1281-753: Is no channel knowledge, there is no beamforming or array gain from diversity coding. Diversity coding can be combined with spatial multiplexing when some channel knowledge is available at the receiver. Multi-antenna MIMO (or single-user MIMO) technology has been developed and implemented in some standards, e.g., 802.11n products. Third Generation (3G) (CDMA and UMTS) allows for implementing space-time transmit diversity schemes, in combination with transmit beamforming at base stations. Fourth Generation (4G) LTE And LTE Advanced define very advanced air interfaces extensively relying on MIMO techniques. LTE primarily focuses on single-link MIMO relying on Spatial Multiplexing and space-time coding while LTE-Advanced further extends

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1342-404: Is required to adjust the phases and amplitude of each transmitter. In a beamformer optimized for spatial diversity or spatial multiplexing, each antenna element simultaneously transmits a weighted combination of two data symbols. Papers by Gerard J. Foschini and Michael J. Gans, Foschini and Emre Telatar have shown that the channel capacity (a theoretical upper bound on system throughput) for

1403-421: Is said to have applied for a patent on Electro telegraphy by means of condensers and induction coils . Pioneers working on wireless devices eventually came to a limit of distance they could cover. Connecting the antenna directly to the spark gap produced only a heavily damped pulse train. There were only a few cycles before oscillations ceased. Braun's circuit afforded a much longer sustained oscillation because

1464-458: Is studied in a sub-discipline called MIMO radar . MIMO technology can be used in non-wireless communications systems. One example is the home networking standard ITU-T G.9963 , which defines a powerline communications system that uses MIMO techniques to transmit multiple signals over multiple AC wires (phase, neutral and ground). In MIMO systems, a transmitter sends multiple streams by multiple transmit antennas. The transmit streams go through

1525-806: Is the ratio between transmit power and noise power (i.e., transmit SNR ). The optimal signal covariance Q = V S V H {\displaystyle \mathbf {Q} =\mathbf {VSV} ^{H}} is achieved through singular value decomposition of the channel matrix U D V H = H {\displaystyle \mathbf {UDV} ^{H}\,=\,\mathbf {H} } and an optimal diagonal power allocation matrix S = diag ( s 1 , … , s min ( N t , N r ) , 0 , … , 0 ) {\displaystyle \mathbf {S} ={\textrm {diag}}(s_{1},\ldots ,s_{\min(N_{t},N_{r})},0,\ldots ,0)} . The optimal power allocation

1586-438: Is transmitted from a different transmit antenna in the same frequency channel. If these signals arrive at the receiver antenna array with sufficiently different spatial signatures and the receiver has accurate CSI, it can separate these streams into (almost) parallel channels. Spatial multiplexing is a very powerful technique for increasing channel capacity at higher signal-to-noise ratios (SNR). The maximum number of spatial streams

1647-412: Is zero if its argument is negative, and μ {\displaystyle \mu } is selected such that s 1 + … + s min ( N t , N r ) = N t {\displaystyle s_{1}+\ldots +s_{\min(N_{t},N_{r})}=N_{t}} . If the transmitter has only statistical channel state information , then

1708-666: The University of Marburg and received a PhD from the University of Berlin in 1872. In 1874, he discovered in Leipzig while he was working there as a secondary school teacher in the Thomasschule , that a point-contact metal–semiconductor junction rectifies alternating current . He became director of the Physical Institute and professor of physics at the University of Strassburg in 1895. In 1897, he built

1769-407: The development of radio , he also worked on wireless telegraphy . In 1897, Braun joined the line of wireless pioneers. His major contributions were the introduction of a closed tuned circuit in the generating part of the transmitter, its separation from the radiating part (the antenna) by means of inductive coupling, and later on the usage of crystals for receiving purposes. Around 1898, he invented

1830-723: The ITU G.hn standard and of the HomePlug AV2 specification. At one time, in wireless the term "MIMO" referred to the use of multiple antennas at the transmitter and the receiver. In modern usage, "MIMO" specifically refers to a class of techniques for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting the difference in signal propagation between different antennas (e.g. due to multipath propagation ). Additionally, modern MIMO usage often refers to multiple data signals sent to different receivers (with one or more receive antennas) though this

1891-680: The Nazi government as a tool of National Socialist scientific propaganda. Nipkow died in Berlin in 1940 two days after his 80th birthday and had an official ceremony organised by the Nazi government. SCHMIDT, Claus-Dietrich, Paul Nipkow. Erfinder des Fernsehens (1860–1940). Sein Leben in den technischen Fortschritt , Lębork Museum, 2009. The only detailed biography on Nipkow. Karl Ferdinand Braun Karl Ferdinand Braun ( German: [ˈfɛʁdinant ˈbʁaʊn] ; 6 June 1850 – 20 April 1918)

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1952-740: The US entered the war, Braun was detained , but could move freely within Brooklyn , New York. Braun died in his house in Brooklyn, before the war ended in 1918. In 1987 the Society for Information Display created the Karl Ferdinand Braun Prize, awarded for an outstanding technical achievement in display technology. MIMO In radio , multiple-input and multiple-output ( MIMO ) ( / ˈ m aɪ m oʊ , ˈ m iː m oʊ / )

2013-419: The broadcasting of pictures. The first television broadcasts used an optical-mechanical picture scanning method, the method that Nipkow had helped create with his disk; he could claim credit for the invention. Nipkow recounted his first sight of television at a Berlin radio show in 1928: "The televisions stood in dark cells. Hundreds stood and waited patiently for the moment at which they would see television for

2074-473: The category "electric apparatuses". This was granted on 15 January 1885, retroactive to 6 January 1884. It is not known whether Nipkow ever attempted a practical realization of this disk, but one may assume that he himself never constructed one. The patent lapsed after 15 years owing to lack of interest. Nipkow took up a position as a designer at an institute in Berlin-Buchloh and did not continue work on

2135-402: The channel matrix and the noise vector, respectively. Referring to information theory , the ergodic channel capacity of MIMO systems where both the transmitter and the receiver have perfect instantaneous channel state information is where ( ) H {\displaystyle ()^{H}} denotes Hermitian transpose and ρ {\displaystyle \rho }

2196-540: The design to multi-user MIMO. In wireless local area networks (WLAN), the IEEE 802.11n (Wi-Fi), MIMO technology is implemented in the standard using three different techniques: antenna selection, space-time coding and possibly beamforming. Spatial multiplexing techniques make the receivers very complex, and therefore they are typically combined with orthogonal frequency-division multiplexing (OFDM) or with orthogonal frequency-division multiple access (OFDMA) modulation, where

2257-564: The development of wireless telegraphy ". The prize awarded to Braun in 1909 depicts this design. Braun experimented at first at the University of Strasbourg. Not before long he bridged a distance of 42 km to the city of Mutzig. In spring 1899, Braun, accompanied by his colleagues Cantor and Zenneck, went to Cuxhaven to continue their experiments at the North Sea. On 24 September 1900 radio telegraphy signals were exchanged regularly with

2318-473: The development of wireless telegraphy". He was a founder of Telefunken , one of the pioneering communications and television companies, and has been called the "father of television" (shared with inventors like Paul Gottlieb Nipkow ), the "great grandfather of every semiconductor ever manufactured" and a co-father of radio telegraphy, together with Marconi. Braun was born in Fulda , Germany, and educated at

2379-936: The end of 2015. The first 4G cellular standard was proposed by NTT DoCoMo in 2004. Long term evolution (LTE) is based on MIMO-OFDM and continues to be developed by the 3rd Generation Partnership Project (3GPP). LTE specifies downlink rates up to 300 Mbit/s, uplink rates up to 75 Mbit/s, and quality of service parameters such as low latency. LTE Advanced adds support for picocells, femtocells, and multi-carrier channels up to 100 MHz wide. LTE has been embraced by both GSM/UMTS and CDMA operators. The first LTE services were launched in Oslo and Stockholm by TeliaSonera in 2009. As of 2015, there were more than 360 LTE networks in 123 countries operational with approximately 373 million connections (devices). MIMO can be sub-divided into three main categories: precoding , spatial multiplexing (SM), and diversity coding . Precoding

2440-404: The energy encountered less losses swinging between coil and Leyden Jars. And by means of inductive antenna coupling the radiator was better matched to the generator. The resultant stronger and less bandwidth consuming signals bridged a much longer distance. Braun invented the phased array antenna in 1905. He described in his Nobel Prize lecture how he carefully arranged three antennas to transmit

2501-709: The ergodic channel capacity will decrease as the signal covariance Q {\displaystyle \mathbf {Q} } can only be optimized in terms of the average mutual information as The spatial correlation of the channel has a strong impact on the ergodic channel capacity with statistical information. If the transmitter has no channel state information it can select the signal covariance Q {\displaystyle \mathbf {Q} } to maximize channel capacity under worst-case statistics, which means Q = 1 / N t I {\displaystyle \mathbf {Q} =1/N_{t}\mathbf {I} } and accordingly Depending on

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2562-594: The first cathode-ray tube (CRT) and cathode-ray tube oscilloscope . The CRT became the cornerstone in developing fully electronic television, being a part of every TV, computer and any other screen set up till the introduction of the LCD screen at the end of the 20th century. It is still mostly called the "Braun tube" in German-speaking countries ( Braunsche Röhre ) and other countries such as Korea (브라운관: Buraun-kwan ) and Japan ( ブラウン管 : Buraun-kan ). During

2623-481: The first time. I waited among them, growing ever more nervous. Now for the first time, I would see what I had devised 45 years ago. Finally, I reached the front row; a dark cloth was pushed to the side, and I saw before me a flickering image, not easy to discern." The system demonstrated was from the company Telefunken . From the early 1930s, total electronic picture scanning, based on the work of Manfred von Ardenne , became increasingly prevalent, and Nipkow's invention

2684-581: The island of Heligoland over a distance of 62 km. Light vessels in the river Elbe and a coast station at Cuxhaven commenced a regular radio telegraph service. Braun went to the United States at the beginning of World War I (before the U.S. had entered the war) to be a witness for the defense in a lawsuit regarding a patent claim by the Marconi Corporation against the wireless station of Telefunken at Sayville, New York . After

2745-410: The mathematical techniques for dealing with mutual interference proved useful to MIMO development. In the mid-1980s Jack Salz at Bell Laboratories took this research a step further, investigating multi-user systems operating over "mutually cross-coupled linear networks with additive noise sources" such as time-division multiplexing and dually-polarized radio systems. Methods were developed to improve

2806-477: The multiple receive antennas and decodes the received signal vectors into the original information. A narrowband flat fading MIMO system is modeled as: where y {\displaystyle \mathbf {y} } and x {\displaystyle \mathbf {x} } are the receive and transmit vectors, respectively, and H {\displaystyle \mathbf {H} } and n {\displaystyle \mathbf {n} } are

2867-449: The performance of cellular radio networks and enable more aggressive frequency reuse in the early 1990s. Space-division multiple access (SDMA) uses directional or smart antennas to communicate on the same frequency with users in different locations within range of the same base station. An SDMA system was proposed by Richard Roy and Björn Ottersten , researchers at ArrayComm , in 1991. Their US patent (No. 5515378 issued in 1996 ) describes

2928-735: The problems created by a multi-path channel are handled efficiently. The IEEE 802.16e standard incorporates MIMO-OFDMA. The IEEE 802.11n standard, released in October 2009, recommends MIMO-OFDM. MIMO is used in mobile radio telephone standards such as 3GPP and 3GPP2 . In 3GPP, High-Speed Packet Access plus (HSPA+) and Long Term Evolution (LTE) standards take MIMO into account. Moreover, to fully support cellular environments, MIMO research consortia including IST-MASCOT propose to develop advanced MIMO techniques, e.g., multi-user MIMO (MU-MIMO). MIMO wireless communications architectures and processing techniques can be applied to sensing problems. This

2989-419: The province of West Prussia , Nipkow experimented in telephony and the transmission of moving pictures. After graduation, he went to Berlin in order to study science. He studied physiological optics with Hermann von Helmholtz , and electro-physics with Adolf Slaby . While still a student he conceived an "electric telescope", mainly known for the idea of using a spiral-perforated disk ( Nipkow disk ), to divide

3050-417: The quality of the signal channel is also critical. A channel emulator can simulate how a device performs at the cell edge, can add noise or can simulate what the channel looks like at speed. To fully qualify the performance of a receiver, a calibrated transmitter, such as a vector signal generator (VSG), and channel emulator can be used to test the receiver under a variety of different conditions. Conversely,

3111-873: The receive antenna array based on differences in "directions-of-arrival." Paulraj was awarded the prestigious Marconi Prize in 2014 for "his pioneering contributions to developing the theory and applications of MIMO antennas. ... His idea for using multiple antennas at both the transmitting and receiving stations – which is at the heart of the current high speed WiFi and 4G mobile systems – has revolutionized high speed wireless." In an April 1996 paper and subsequent patent, Greg Raleigh proposed that natural multipath propagation can be exploited to transmit multiple, independent information streams using co-located antennas and multi-dimensional signal processing. The paper also identified practical solutions for modulation ( MIMO-OFDM ), coding, synchronization, and channel estimation. Later that year (September 1996) Gerard J. Foschini submitted

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3172-407: The received signal gain – by making signals emitted from different antennas add up constructively – and to reduce the multipath fading effect. In line-of-sight propagation , beamforming results in a well-defined directional pattern. However, conventional beams are not a good analogy in cellular networks, which are mainly characterized by multipath propagation . When the receiver has multiple antennas,

3233-542: The statistical properties of the channel, the ergodic capacity is no greater than min ( N t , N r ) {\displaystyle \min(N_{t},N_{r})} times larger than that of a SISO system. A fundamental problem in MIMO communication is estimating the transmit vector, x {\displaystyle \mathbf {x} } , given the received vector, y {\displaystyle \mathbf {y} } . This can be posed as

3294-430: The transmit beamforming cannot simultaneously maximize the signal level at all of the receive antennas, and precoding with multiple streams is often beneficial. Precoding requires knowledge of channel state information (CSI) at the transmitter and the receiver. Spatial multiplexing requires MIMO antenna configuration. In spatial multiplexing, a high-rate signal is split into multiple lower-rate streams and each stream

3355-533: The transmitter sends a Pilot signal and the receiver learns the state of the channel (i.e., H {\displaystyle \mathbf {H} } ) from the received signal Y {\displaystyle Y} and the Pilot signal X {\displaystyle X} . Recently, there are works on MIMO detection using Deep learning tools which have shown to work better than other methods such as zero-forcing. MIMO signal testing focuses first on

3416-413: The transmitter's performance under a number of different conditions can be verified using a channel emulator and a calibrated receiver, such as a vector signal analyzer (VSA). Understanding the channel allows for manipulation of the phase and amplitude of each transmitter in order to form a beam. To correctly form a beam, the transmitter needs to understand the characteristics of the channel. This process

3477-459: The transmitter/receiver system. The random phases of the sub-carrier signals can produce instantaneous power levels that cause the amplifier to compress, momentarily causing distortion and ultimately symbol errors. Signals with a high PAR ( peak-to-average ratio ) can cause amplifiers to compress unpredictably during transmission. OFDM signals are very dynamic and compression problems can be hard to detect because of their noise-like nature. Knowing

3538-532: Was a German electrical engineer , physicist and inventor. Braun contributed significantly to the development of radio when he invented the phased array antenna in 1905, which led to the development of radar , smart antennas and MIMO . He built the first cathode-ray tube , which led to the development of television . He also built the first semiconductor . Braun shared the 1909 Nobel Prize in Physics with Guglielmo Marconi "for their contributions to

3599-589: Was acquired by Broadcom in 2010. WiMAX was developed as an alternative to cellular standards, is based on the 802.16e standard, and uses MIMO-OFDM to deliver speeds up to 138 Mbit/s. The more advanced 802.16m standard enables download speeds up to 1 Gbit/s. A nationwide WiMAX network was built in the United States by Clearwire , a subsidiary of Sprint-Nextel , covering 130 million points of presence (PoPs) by mid-2012. Sprint subsequently announced plans to deploy LTE (the cellular 4G standard) covering 31 cities by mid-2013 and to shut down its WiMAX network by

3660-474: Was acquired by Intel in 2003. Neither Clarity Wireless nor Iospan Wireless shipped MIMO-OFDM products before being acquired. MIMO technology has been standardized for wireless LANs , 3G mobile phone networks, and 4G mobile phone networks and is now in widespread commercial use. Greg Raleigh and V. K. Jones founded Airgo Networks in 2001 to develop MIMO-OFDM chipsets for wireless LANs. The Institute of Electrical and Electronics Engineers ( IEEE ) created

3721-418: Was no longer essential to the further development of television. The world's first regular television service , started in Berlin in 1935, was named Fernsehsender "Paul Nipkow" after Nipkow – the "spiritual father" of the core element of first-generation television technology. He became honorary president of the "television council" of the "Imperial Broadcasting Chamber". Nipkow's glory was used by Hitler and

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