User Review( votes)
5G is the latest technology which supports eMbb,mMTC,uRLLC
What is 5G – The Technology
Just as the previous generations of wireless cellular technology the fifth generation, 5G technology come with lots of improvements, & includes lots of latest technology, like a smart vehicle, Human-machine,5G medical, sensor and IOT. The 5th generation (5G) wireless access technology, known as new radio (NR), will address a variety of usage scenarios from enhanced mobile broadband (eMBB) to ultra-reliable low-latency communications (URLLC) to massive machine type communications (mMTC). NR can meet the performance requirements set by the international telecommunication union (ITU) for international mobile telecommunications for the year 2020.The third-generation partnership project (3GPP) is a global standard-development organization and has been developing 5G NR over the past few years. After initial studies, 3GPP approved a work item in March 2017 for NR specifications as part of Release 15. 3GPP agreed to a proposal to accelerate the 5G schedule to complete non-standalone (NSA) NR by December 2017, while standalone (SA) NR was scheduled to be completed by June 2018. In NSA operation, long-term evolution (LTE) is used for initial access and mobility handling while the SA version can be deployed independently from LTE. A major milestone was reached in December 2017 with the approval of the NSA NR specifications and the SA version was completed in June 2018. The last step for Rel-15 is a late drop that will be completed by December 2018. The late drop will include more architecture options, e.g., the possibility to connect 5G NodeBs (gNB) to the evolved packet core (EPC) and operating NR and LTE in multi connectivity mode wherein NR is the master node and LTE is the secondary node.
5G is different than 4G because of multiple numbers of small cell antenna network. The primary new technologies are such as millimeter wave bands and massive MIMO (Multiple Input Multiple Output), Network slicing, Bandwidth part, Scalable numerology, Beam Management.
Millimeter wave bands, which occupies frequencies between approximately 30 – 300 GHz offer speeds as high as 10 to 20 Gbit/s. The massive MIMO technology reaches speeds of 490 Mbit/s at a bandwidth of 3.5 – 4.2 GHz.
5G Network Key Technology
Heterogeneous use cases diverse requirements
From IMT Advanced to IMT 2020
3GPP Requirements for NR
Three main 5G Use Cases
5G Key Pillars
5G requirements vs. Usage scenario
3GPP 5G Study Item
NR – Key technology features
Scalable NR Numerology
To satisfy this asymmetric and dynamic traffic demand, dynamic TDD is one promising solution since the UL/DL transmission direction can be changed dynamically to adapt the instantaneous traffic variation
Dynamic TDD, enhanced interference mitigation and traffic adaptation (eIMTA) has been widely studied since LTE Rel.12 where the UL/DL transmission direction is changed based on seven TDD configurations
Massive MIMO is the currently most compelling sub-6 GHz physical-layer technology for future wireless access. The main concept is to use large antenna arrays at base stations to simultaneously serve many autonomous terminals, as illustrated in Figure 1. The rich and unique propagation signatures of the terminals are exploited with smart processing at the array to achieve superior capacity. Massive MIMO splendidly offers the two most desirable benefits:
- Excellent spectral efficiency, achieved by spatial multiplexing of many terminals in the same time-frequency resource. Efficient multiplexing requires channels to different terminals to be sufficiently different, which has been shown to hold, theoretically and experimentally, in diverse propagation environments. Specifically, it is known that Massive MIMO works as well in line-of-sight as in rich scattering
2. Superior energy efficiency, by virtue of the array gain, that permits a reduction of radiated power. Moreover, the ability to achieve excellent performance while operating with low-accuracy signals and linear processing further enable considerable savings.
The introduction of the new bandwidth part concept allows flexible and dynamic configuration of UE’s operating bandwidth, which will make NR an energy-efficient solution despite the support of wide bandwidth
Wide bandwidth has a direct impact on the peak and user experienced data rates. However, since UEs do not always demand high data rates, the use of wide BW may imply higher idling power consumption from both RF and baseband signal processing perspectives. In this regard, there is a newly developed concept of BWP for NR that provides a means of operating UEs with smaller BW than the configured CBW
- There may be power savings in some scenarios due to the possibility to operate the RF-baseband interface with a lower sampling rate and reduced baseband processing needed to transmit or receive with narrower bandwidth.
- UE RF bandwidth adaptation can provide UE power saving at least if carrier bandwidth before adaptation is large. One note here is that as the UE power consumption is quite dependent on each modem and RF implementation, it is difficult to expect a quantitative power saving gain.
Fifth-generation networks need to integrate multiple services with various performance requirements — such as high throughput, low latency, high reliability, high mobility, and high security — into single physical network infrastructure, and provide each service with a customized logical network (that is, network slicing). The Third-Generation Partnership Project (3GPP) has identified network slicing as one of the key technologies to achieve the aforementioned goals in future 5G networks.
Millimeter wave spectrum designed from 30 to 300 GHz is recognized as millimetre-wave, And frequency bands at 60 and 77 GHz. One of the key advantages of millimeter wave communication technology is a large amount of spectral bandwidth available. The bandwidth available in the 70 GHz and 80 GHz bands, a total of 10 GHz, is more than the sum total of all another licensed spectrum available for wireless communication. With such wide bandwidth available, millimeter wave wireless links can achieve capacities as high as 10 Gbps full duplex, which is unlikely to be matched by any lower frequency RF wireless technologies. The availability of this extraordinary amount of bandwidth also enables the capability to scale the capacity of millimeter wave wireless links as demanded by market needs. Typical millimeter wave products commonly available today operate with spectral efficiency close to 0.5 bits/Hz. However, as the demand arises for higher capacity links, millimeter wave technology will be able to meet the higher demand by using more efficient modulation schemes.
An issue with current mobile-communication technologies is the number of transmissions carried by network nodes regardless of the amount of user traffic. Such “always-on” transmissions include, for example, signals for base-station detection, broadcast of system information, and always-on reference signals for channel estimation. Under typical traffic conditions for which LTE was designed, such transmissions constitute only a minor part of the overall network transmissions and thus have a relatively small impact on the network performance. However, in very dense networks deployed for high peak data rates, the average traffic load per network node can be expected to be relatively low, making the always-on transmissions a more substantial part of the overall network transmissions.
The always-on transmissions have two negative impacts:
- They impose an upper limit on the achievable network energy performance, and
- They cause interference to other cells, thereby reducing the achievable data rates.
The ultra-lean-design principle aims at minimizing the always-on transmissions, thereby enabling higher network energy performance and higher achievable data rates.
Inter working and LTE coexistence
As it is difficult to provide full coverage at higher frequencies, interworking with systems operating at lower frequencies is important. In particular, a coverage imbalance between uplink and downlink is a common scenario. The higher transmit power for the base station compared to the mobile device results in the downlink achievable data rates often are bandwidth limited, making it more relevant to operate the downlink in the higher spectrum where wider bandwidth may be available. In contrast, the uplink is more often power limited, reducing the need for wider bandwidth. Instead, higher data rates may be achieved on the lower-frequency spectrum, despite less available bandwidth, due to less radio-channel attenuation. Through interworking, a high-frequency NR system can complement a low-frequency system. The lower frequency system can be either NR or LTE, and NR supports interworking with either of these. The interworking can be realized at different levels, including intra-NR carrier aggregation, dual connectivity2 with a common packet data convergence protocol (PDCP) layer, and handover. However, the lower frequency bands are often already occupied by current technologies, primarily LTE. Furthermore, additional low-frequency spectrum is planned to be deployed with LTE in a relatively near future. LTE/NR spectrum coexistence, that is, the possibility for an operator to deploy NR in the same spectrum as an already existing LTE deployment has therefore been identified as a way to enable early NR deployment in lower frequency spectrum without reducing the amount of spectrum available to LTE.
Two co-existence scenarios were identified in 3GPP and guided the NR design. In the first scenario (left part of Figure II-3) there is LTE/NR co-existence in both downlink and uplink. Note that this is relevant for both paired and unpaired spectrum although paired spectrum is used in the illustration. In the second scenario (right part of Figure II-3) there is coexistence only in the uplink transmission direction, typically within the uplink part of lower-frequency paired spectrum, with NR downlink transmission taking place in spectrum dedicated to NR, typically at higher frequencies. This scenario attempts to address the uplink-downlink imbalance discussed above. NR supports a supplementary uplink (SUL) to specifically handle this scenario.
Refrence: 3Gpp.org,Zte,intel,5G fundamental book,qualcom,ericsson