Local UE does not provide an IP BS Manager

The UE does not provide an IP BS Manager. The end-to-end IP QoS bearer service towards the remote terminal is controlled from the GGSN. The scenario assumes that the GGSN supports DiffServ functions, and the backbone IP network is DiffServ enabled. In this scenario, the control of the QoS over the UMTS access network (from the UE to the GGSN) may be performed either from the terminal using the PDP context signaling or from the SGSN by subscription data. 

The IP QoS for the downlink direction is controlled by the remote terminal up to the GGSN. The GGSN will apply receiver control DiffServ edge functions and can reclassify the data (remarking the DiffServ Code Point = DSCP). This may affect the QoS applied to the data over the UMTS access (the TFT may use the DSCP to identify the data to be allocated to the PDP context). 

The end-to-end QoS is provided by a local mechanism in the UE, the PDP context over the UMTS access network, DiffServ through the backbone IP network, and DiffServ in the remote access network in the scenario shown in the figure below. The GGSN provides the interworking between the PDP context and the DiffServ function. However, the interworking may use information about the PDP context which is established, or be controlled from static profiles, or dynamically through other means such as proprietary of HTTP based mechanisms. The UE is expected to be responsible for the control of the PDP context, but this may instead be controlled from the SGSN by subscription. 

3GPP Concept of QoS

3GPP Standard TS 23.207 provides the framework for end-to-end GPRS and UMTS.  The end-to-end QoS architecture is provided in Figure below. It’s describes the interaction between the TE/MT (Terminal Equipment/Mobile Terminal) Local Bearer Service, the GPRS Bearer Service, and the External Bearer Service, and how these together provide Quality of Service for the End-to-End Service. 

It’s also describes IP level mechanisms necessary in providing end-to-end Quality of Service and possible interaction between the IP level and the GPRS level, as well as the application level and the IP level. This covers different architectural aspects of the end-to-end Quality of Service concept and architecture with varying level of detail. In general, other specifications shall be referred to for further details; these other specifications enable the reader to acquire the full understanding of the end-to-end Quality of Service concept and architecture. 

QoS Management Functions in the Network: to provide IP QoS end-to-end, it is necessary to manage the QoS within each domain. An IP BS (Base Station) Manager is used to control the external IP bearer service. Due to the different techniques used within the IP network, this communicates to the UMTS BS manager through the Translation function. The QoS management functions for controlling the external IP bearer services and how they relate to the UMTS bearer service QoS management functions.

QoS Conceptual Model: there are many different end-to-end scenarios that may occur from an UE connected to an UTMS network. The following examples depict how end-to-end QoS will be delivered for a number of scenarios that are considered to be significant. 

The Concept of QoS by ETSI

ETSI standard TS 102 250-2 v2.2.1 (2011) covering the QoS aspects for popular services in GSM and 3G networks. The standard divided into 6 parts book that identified below: 

•  ETSI TS 102 250 Part 1 identifies QoS criteria for popular services in GSM and 3G networks. They are considered to be suitable for the quantitative characterization of the dominant technical QoS aspects as experienced from the customer perspective. 

•  ETSI TS 102 250 Part 2 defines QoS parameters and their computation for popular services in GSM and 3G networks. 

•  ETSI TS 102 250 Part 3 describes typical procedures used for QoS measurements over GSM, along with settings and parameters for such measurements. 

•  ETSI TS 102 250 Part 4 defines the minimum requirements of QoS measurement equipment for GSM and 3G 

•  ETSI TS 102 250 Part 5 specifies test profiles which are required to enable benchmarking of different GSM or 3G networks both within and outside national boundaries. 

•  ETSI TS 102 250 Part 6 describes procedures to be used for statistical calculations in the field of QoS measurement of GSM and 3G networks using probing systems.  

General Consideration: ETSI identifies QoS criteria for popular services in GSM and 3G. They are considered to be suitable for the quantitative characterization of the dominant technical QoS aspects as experienced from the customer perspective. The criteria are described by their name and a short description from the customer point of view.

Phases of Service from the Customer's Point of View 

Figure shows different phases (Quality of Service aspects) during service use from the customer’s point of view. The five QoS aspects are: 

1.Network Availability: is the probability of a telecommunications service that can be offered to customers through a network infrastructure. 

2.Network Accessibility: probability that users can register on the network to be successful so that the network can provide telecommunication services. Network can only be accessed when it is available to the user. 

3.Service Accessibility: probability that the user can access the service you want to use., If the customer wants to use a service, the network operator should provide him as fast as possible access to the service 

4.Service Integrity: describes QoS while using the service and contains elements such as the quality of the content being transmitted, such as sound quality, video quality, and the number of bits transmitted error in the file. Service integrity can only be calculated if the service is accessible to success. 

5.Service Retainability: Service retainability describes the termination of services, in accordance with or against the will of the user. Explains how to end or terminate a service, whether or not the will of the user. Examples of service retain ability parameter are call cut-off ratio or the data cut-off ratio. 

Grade of Service

ITU-T Recommendation E.771 proposes network Grade of Service (GOS) parameters for current and evolving land mobile services. These parameters are defined, and their target values specified, assuming that the network and the network components are operating in their normal mode (i.e. are fully operational). Further, the parameters and their target values assume normal (as opposed to distress or emergency) traffic. 

In this Recommendation, the following traffic GOS parameters are specified for mobile circuit switched services: 

•Post Selection Delay: defined as the time interval from the instant the first bit of the initial SETUP message containing all the selection digits is passed by the calling terminal to the access Signaling system until the last bit of the first message indicating ccall disposition is received by the calling terminal (ALERTING message in case of successful call). 

•Answer signal delay: defined as the time interval from the instant that the called terminal passes the first bit of the CONNECT message to its access Signaling system until the last bit of the CONNECT message is received by the calling terminal. 

•Call release delay: defined as the time interval from the instant the DISCONNECT message is passed by the user terminal which terminated the call to the access Signaling system, until the RELEASE message is received by the same terminal (indicating that the terminals can initiate/receive a new call). 

•Probability of end-to-end blocking: defined as the probability that any call attempt will be unsuccessful due to a lack of network resources. 

•Probability of unsuccessful land cellular handover: defined as the probability that a handover attempt fails because of lack of radio resources in the target cell, or because of a lack of free resources for establishing the new network connection. The failure condition is based either on a specified time interval since the handover request was first issued or on a threshold on signal strength. 

User Perception of QoS vs Operational Performance in Practical

Why are any differences between the results of measurements of QoSE (QoS Experience by the user) and QoSD (QoS Delivered by the provider), whereas the measurement of QoS and network performance are not contradictory? 

In practice, many factors that influence the customer's perception of the QoS service they received from the provider. 

In general, the perception of the customer is to compare the quality of service that they feel with the quality they expect. Customer expectations are influenced by the rates they pay and the information that they know from the media and from books. In general, if a customer feels an expensive, then their expectations for service quality is high as well. 

Provider of telecommunications equipment owned or rented, and operates with the standard of performance they called KPI (Key Performance Indicator). The better prepared KPI, and the more realistic service rates, the correlation between customer expectations for QoS performance telecommunications systeM, will increase. 

To better understand the expectations of its customers, the provider must have good customer service. Customer service should be a very good understanding of operational performance measured through Key Performance Indicators, as well as understand the relationship between customer complaints with performance indicators. 

The task is customer service is two-way. On the one hand, they should be able to answer customer complaints properly, according to the technical conditions of operation. On the other hand, they should be able to give direction to the company, the translation of the customer's wishes into technical performance criteria. 

Providers that are less, in general, ignore the customer service. As a result, customers will be frustrated. Customers have been disappointed, because he felt the complaint was not answered correctly. Provider engineers also depressed, because it was already successfully operating the device in accordance with technical standards, but it is still considered bad by the company who read so many reports of customer disappointment. 

QoSE (QoS Experienced by the User)

QoS experienced by users reflect the subjective point of view of a user in certain circumstances they experienced. Customer satisfaction is one of the driving factors for this type of QoS. In general, QoSE described in nontechnical parameters. Telecom service providers can measure the level of QoSE by conducting a survey to its customers or to seek advice and input from them. At this stage, a user combines personal experience with the expected technical quality of the service it uses. In addition to technological aspects, there are several other factors that affect the level of QoSE. Some of these factors such as starting from the signing of the contract between the user and the service provider, the service provider the ability to handle probleM faced by customers, and the overall relationship between the customer and the service provider. Thus, it can be concluded that QoSE quite difficult to measure because there are several factors "hidden" are not easy to identify. 

QoSD (QoS Delivered by the Service Provider)
QoSD reflect the level of QoS that has been successfully achieved by the telecom service providers. QoSD can test the ability of a telecommunications service provider to deliver the promised QoS.

Radio Access Network - RAN

Here’s where we all look at the radio network. It is the most expensive part of the network. It will have many parts and pieces and could incorporate even more parts as the network matures. Let’s start by explaining that RAN means “Radio Access Network,” and it will have everything outside between the core and the end user. Most people just think of the radios, but the network is more than just radios and core. It is a complex system of connections that need to talk to each other and the core and the user’s equipment, the UE. The UE could be a smartphone, a laptop, a device in a meter or a video camera, or anything that can connect to the network. Don’t limit yourself to thinking it is just LTE because it could be Wi-Fi or another type of wireless format. 4G is a collection of high-speed formats and 5G will only add more formats and complexity to the network. It’s something that you need to be aware of when moving ahead. Although Wi-Fi never panned out as the carriers had hoped, it is still a major part of the network for offload. 

Remember that this book is about deployments. We’re not diving too deep into the architecture. The heart of the RAN is the BTS, base transceiver station. The radio itself. The eNodeB is much more advanced than the radios of old. It could be any spectrum, but to give you an idea of what is in it I made a drawing below that is typical of today’s BTS. 

Remember that there is more to the BTS than just receive or transmitter. It is also a router that connects the backhaul which could have a microwave. The BTS also has batteries to survive outages. Power backup will be in most macro, and small cells Wi-Fi usually won’t have power backup. Now that we have 5G you will also see servers at more sites to support cloud and edge computing. We need the radio heads at macro sites and antennas. Today’s macro BTS have separated the RF from the controller. It is the evolution that has made things so different. Small cells, on the other hand, are an all in one unit. 

TDD and FDD Formats

There are two technologies for LTE. For LTE, they have FDD and TDD which both are viable options. Both are viable options. They are both used by carriers in the USA although FDD has been the choice in the past.  

·       What is FDD? FDD – Frequency Division Duplex is something that was used commonly in 3G. It’s paired spectrum with an uplink band and a downlink band in their specific spectrum. For 1G, 2G, and 3G this was common so you could have a talk and receive channel in the system. There is a guard band in between the transmit band and the receive band. FDD was very popular with GSM and CDMA. It is very difficult to take advantage of MIMO antenna technology in FDD compared to TDD.  

·       What is TDD? TDD – Time Division Duplex is where there is one large piece of spectrum used for uplink or downlink. Any part or percentage can be assigned to be the uplink or downlink. If you have 20MHz of bandwidth available, then you’re not locked into 10MHz up and 10MHz down like FDD. Instead, you have full control over how much goes up and comes down. The downside that some carriers had was the timing of the spectrum, and it's higher bands that have this. However, Wi-Fi spectrum is pretty much all TDD, and it works quite well for data. On the other hand, WiMAX used TDD, and it seemed to be taking off but it never fully blossomed and was cast aside for LTE. TDD makes MIMO technology easier to use because it is all in one band. 

So, what can LTE do? It can do both, and it does do both. Just not the same equipment. You could have equipment do either LTE-TDD and LTE-FDD. Both are released commercially as well as part of the 3GPP standard. When you look at the deployments, it helps to know which format will be deployed. You see, FDD may need two antennas or a combiner to work on a tower. While TDD is all in the same spectrum and the same antenna is used for both transmit and receive. The way that today’s radio heads work it isn’t much of an issue anymore because they can handle the formats quite well. In 2016, you still can’t run them together in the same radio head, although the OEMs are working towards that functionality. Antennas are being designed to run both together by adding more ports and more weight to the antennas. 

Note that Wi-Fi is TDD and ZigBee is TDD. Most Bluetooth is TDD. TDD appears to be the choice moving forward. Most 2G and 3G systems were FDD, and they are being phased out. 

Carriers are learning that when everything becomes truly digital in IP format that it will matter less and less for the BTS, but antennas and spectrum efficiency become more important. As of 2016, most of the carriers already have implemented VoLTE into their main networks, all except maybe Sprint who was still relying on CDMA to carry the voice. The carriers know that when they convert VoLTE, it should be the last step to dismantling the 3G networks, saving them money in the long run by retiring 2G and 3G systems. 

4G spectrum, soon to be part of 5G Spectrum

The spectrum is whatever they could get from the FCC in the USA. They get it from the spectrum auctions that the FCC holds. There is always a need for more although some carriers have yet to deploy all of what they have. With 3G they could use smaller swaths of bandwidth. 4G changed that, and 5G will only make them want more. 

Spectrum is tough to show because there is 4G spectrum for auction here in the USA. I realize that spectrum goes to the highest bidder, (in my opinion small businesses suffer). However, the rush to get spectrum has diminished by the carriers learning to make the most of the existing spectrum. While the bands are small, they have been using something called carrier aggregation to combine spectrum bands to look like one big pipe, which is awesome. The OEMs have worked to put together 2 or more bands so that they look like one big band making the end user happy with more throughput.

In the USA, there are many bands. 

•710 to 716MHz paired with 740 to 746MHz used by AT&T 

•746 to 757MHz paired with 776MHz to 787MHz used by Verizon Wireless 

•806 to 866MHz and 869MHz which belongs to Sprint, this is the old Nextel band. 

•1710 to 1785MHz and 1805 to 1880MHz is T-Mobile AWS spectrum. 

•1850 to 1990 MHz is Sprint FDD spectrum. 

•2.5GHz to 2.7GHz is Sprint TDD spectrum. 

•More and more, it would take some time to break them all out. So much spectrum is out there, and the carriers are grabbing what they can.