5G millimeter wave

5G millimeter wave features:

Millimeter waves have short wavelengths that range from 10 millimeters to 1 millimeter. 

To achieve higher data rate requirement in the order of 10 Gbps, 5G technology has been developed. 

The specifications are published in the 3GPP Release 15 and beyond. 

5G has different frequency ranges sub 6 GHz (5G macro optimized), 3-30 GHz (5G E small cells) and 30-100 GHz (5G Ultra Dense).

The frequency bands which lies between 30 GHz to 300 GHz is known as millimeter wave. 

This is due to the fact that wavelength of electro-magnetic wave will be in millimeter range at these frequencies. 

There are many advantages and disadvantages of mm wave.

Due to growth of large number of mobile data subscribers, need for larger bandwidth arises. 

The fact is bandwidth is limited in the available mobile frequency spectrum which is below the mm wave band. 

Due to this millimeter wave band has been explored as mobile frequency spectrum by operators due to its support for larger bandwidth. 

Though penetration loss is higher at these mm wave frequencies as these frequencies can not penetrate walls and certain objects in the buildings. 

Moreover mm wave frequencies get attenuated due to rain. After careful inclusion of all these factors in the RF link budget calculation, mm wave can be strong future for the mobile data broadband market.

Data rate                           => min 10 gbps

Modulation types                    => CP-OFDMA <40GHz < SC

modulation frequency                => Upto 100GHZ

Bandwidths                          => 500 MHZ to 2 GHZ

Distance coverage                   => upto 250 meters

Frame                               => TDD

MIMO                                => Massive MIMO

DRX

Discontinuous Reception (DRX) 

One of the important activities performed by UE during RRC Idle mode is listening to paging message.

The UE should listen to the paging message to know about incoming calls. In LTE, the UE needs to monitor PDCCH continuously (every 1ms) for P-RNTI to listen to paging message and this drains UE battery power heavily. 

Instead, if the UE is allowed to monitor P-RNTI in PDCCH, only at predetermined period say every 60ms or 100ms, it will reduce UE’s power consumption.

The process of monitoring PDCCH discontinuously for P-RNTI to listen to paging message during RRC idle state is known as Discontinuous Reception (DRX) in RRC_Idle. 

This provides method for the UE to micro-sleep even in the active state to reduce power consumption while providing high QOS and connectivity. Meaning that UE is not monitoring the PDCCH in the given sub frame and it is allowed to go UE in a power saving mode.

Discontinuous Reception for Paging:

Paging is a procedure to transmit paging message to the UE in RRC Idle mode or EMM registered state. Paging message may be triggered either by MME in core network or eNB in Radio Access Network.

Paging information for the UE is being carried on the PDSCH in the resource blocks indicated by the PDCCH. 

Paging indication on PDCCH is single fixed indicator (FFFE) called the paging RNTI (P-RNTI)

Different group of UE's monitor different sub frames for their paging messages.

UE's in idle mode monitor the PDCCH channel for P-RNTI used for paging  to receive paging message from eNB.

The UE needs to monitor the PDCCH only at certain UE specific paging occasion, i.e. only at specific subframe in specific radio frame. At other times the UE may go for sleep mode to save battery power.

How UE can find out paging frame and paging occasion for its paging message:

Paging Frame (PF )   : One paging frame (PF) is one Radio 
                       Frame in which the UE is looking for 
                       paging message. One Paging Frame may 
                       contain one or multiple Paging 
                       Occasion(s).

Paging Occassion (PO): It is a sub-frame where there may be 
                       P-RNTI transmitted on PDCCH
                       addressing the paging message for the 
                       UE.There is always only one paging 
                       occasion for each UE in a DRX cycle.

To find out PF (Paging Frame) and PO (Paging Occasion ), the UE uses DRX parameters broadcasted in the system information SIB2.

What are the DRX Parameters ?

1] DRX cycle: Indicates the number of radio frames in the paging
            cycle. Larger the value of this parameter, lesser 
            the UE battery power consumption. 
            Whereas smaller the value of DRX cycle, increase in
            the UE battery power consumption

2] nB       : This cell specific parameter indicates number of 
            paging occasions in a cell specific DRX cycle.
            Configuration of nB value depends on paging
            capacity required in a cell. The larger the value 
            of nB is configured to, the larger the paging 
            capacity. Likewise, the smaller the paging capacity
            when the value of nB is smaller.

With this we can infer that a maximum of 1 radio frame is available per DRX cycle of the UE for paging. Also, the minimum
of 1 sub frame per radio frame (nB ≤ 1T) and maximum 
of 4 sub frames (for nB=4T) are available for paging message for the UE.

Calculation of Paging Frame Number:

Both the eNB and the UE calculate the Paging Frame number by the following relation:

Paging Frame Number = SFN mod T = (T/N) * (UE ID MOD N)

The eNB will receive UE_ID from the MME in PAGING S1AP message as "UE Identity Index Value" for MME initiated paging message.

The UE will find out the UE_ID by using the relation IMSI mod 1024

The IMSI is given as sequence of digits of type Integer (0..9). The IMSI shall, in the formulae above, be interpreted as a decimal integer number, where the first digit given in the sequence represents the highest order digit.

For example: IMSI = 12 (digit1=1, digit2=2). In the calculations, this shall be interpreted as the decimal integer "12", not "1x16+2 = 18".

Calculation of Paging Occasion (Paging Sub frame Number in a Paging Frame)

Paging Occasion is a function of i_s, Ns and predefined sub frame pattern i_s => Index pointing to predefined table corresponding subframe.

= Floor (UE_ID/N)MOD Ns

Paging Occasion for the UE is obtained from the predefined subframe pattern (36.304 section 7.2, shown below for quick reference) based on the value of Ns, i_s. For example, if Ns=2 and i_s = 1, UE interprets that sub frames 4 and 9 are configured for paging in the cell and subframe 9 is paging occasion for it.

5G

5G Technology:

Then main purpose of 5G is high data rate, reduced latency, energy saving, cost reduction, higher system capacity, and massive device connectivity. 

5G speed:

Speed up to 20 gigabits per second with millimeter waves of 15 gigahertz and higher frequency

5G phase:

1st phase  :    March 2019

2nd phase  :    March 2020

Companies involved in the deployment:

•  Huawei 
•  Intel
•  Qualcomm

Modes of deployment:

1]Non-Standalone mode:

Non-Standalone (NSA) mode of 5G NR refers to an option of 5G NR deployment that dependent on the control plane of existing LTE network for control functions, while 5G NR exclusively focused on user plane.

2]Standalone mode:

Standalone (SA) mode of 5G NR refers to using 5G cells for both signalling and data transfer.

It includes the new 5G Package Core architecture instead of relying on the 4G Evolved Package Core.

Interfaces offered by 5G:

1. NR 5G   : NR (New Radio) 5G is a new air interface developed for the 5G            network
2. TF 5G  : Verizon 5G Technical Forum
3. SIG 5G : 5G SIG is another pre-standard specification of 5G             developed by KT.

How 5G works:

5G wireless signals will be transmitted via large numbers of small cell stations located in places. The use of multiple small cells is necessary because the millimeter wave spectrum -- the band of spectrum between 30 GHz and 300 GHz that 5G relies on to generate high speeds -- can only travel over short distances.

5G use lower-frequency spectrum to  reach a greater distances.