12/17/2023 0 Comments Downlink comThe transceiver structure of OFDM with FFT/IFFT enables scalable bandwidth operation with a low complexity, which is one of the major objectives of LTE.This can make a big difference especially in slow time-varying channels. As shown in Chapter 4, it is possible to exploit frequency-selective scheduling with OFDM-based multiple access (OFDMA), while HSPA only schedules in the time domain.As shown in Chapter 3, OFDM is efficient in combating the frequency-selective fading channel with a simple frequency-domain equalizer, which makes it a suitable technique for wireless broadband systems such as LTE.We summarize some key advantages of OFDM that motivate using it in the LTE downlink: The downlink transmission is based on OFDM with a cyclic prefix (CP), which was described in Chapter 3 along with the associated multiple access scheme described in Chapter 4. On the other hand, a scalable SC-FDMA transmission/ multiaccess technique is used in the uplink since this reduces the peak-to-average power ratio (PAPR) of the transmitted signal. In the downlink, a scalable OFDM transmission/multiaccess technique is used that allows for high spectrum efficiency by utilizing multiuser diversity in a frequency selective channel. In this and the next section, we describe downlink and uplink radio transmission schemes, respectively. In LTE, the downlink and uplink use different transmission schemes due to different considerations. At Mobile World Congress 2021, a few months after Elisa conducted its 8Gbit/s downlink demo, Keysight and Qualcomm showcased a 10Gbit/s data connection using 5G new radio dual connectivity (NR-DC).Learn More Buy 6.3 Downlink OFDMA Radio Resources There's also Keysight Technologies to consider as a speed contender. Samsung, along with Verizon and Qualcomm – in a lab trial conducted late last year – managed "only" 711 Mbit/s using aggregated bands of mmWave spectrum. Earlier this year, and in collaboration with Qualcomm, the vendor demoed 5G download speeds of 8.08 Gbit/s in its lab in Plano, Texas.ĥG uplink speeds still seem a bit off the Nokia Arena pace, however. Samsung, too, has clocked up fast 5G throughout. According to the official announcement, they will be able to take advantage of "enhanced video capture" to support ultra-high quality live reporting and content delivered to mobile devices and televisions.ĥG tech, added Nokia, can also help out with improving venue security. Moreover, visitors to the Arena are promised the ability to watch live performances from 360-degree camera locations via VR headsets, and all from the "comfort of their seats."īroadcasters look set to benefit, too. Augmented reality content for smartphones or wearable devices for immersive experiences also got a mention. These included real-time multi-user 8K ultra-high-definition video streaming. The three companies highlighted the possibility of new "at-venue data services," courtesy of higher 5G uplink speeds. " will deliver incredible and enhanced services to visitors of the Nokia Arena," said Sami Komulainen, Elisa's EVP of production. The Finnish operator expects the "solution" to be "fully deployed" next year, with fans attending Nokia Arena – as far as Light Reading can tell – likely the first beneficiaries. The 5G uplink was put through its paces at the Nokia Arena in Tampere, an indoor stadium with access to Elisa's 5G mmWave spectrum. Nokia's carrier aggregation tech, which included four component carriers of 100MHz, was also used in the trial. The demo involved a Nokia AirScale basestation and Qualcomm's Snapdragon X65 5G Modem-RF System "featuring fourth-generation QualcommQTM545 mmWave antenna modules." Again, working with Nokia and Qualcomm – and using 26GHz mmWave spectrum (as was the case with the high-speed downlink test) – Elisa has apparently demonstrated "record-breaking" 5G uplink speeds of 2.1 Gbit/s. The trio claimed at the time it was the fastest 5G speed ever recorded.Įlisa has now turned its attention to 5G uplink throughput. Finnish operator Elisa likes breaking 5G speed records.Ībout 20 months ago, working in collaboration with Nokia and Qualcomm, Elisa clocked up 8 Gbit/s on the downlink in test conditions.
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