Saturday, July 3, 2010
9 LIMITATIONS OF GPRS : -
It should already be clear that GPRS is an important new enabling mobile data service which offers a major improvement in spectrum efficiency, capability and functionality compared with today's nonvoice mobile services. However, it is important to note that there are some limitations with GPRS, which can be summarized as:
LIMITED CELL CAPACITY FOR ALL USERS :
GPRS does impact a network's existing cell capacity. There are only limited radio resources that can be deployed for different uses- use for one purpose precludes simultaneous use for another. For example, voice and GPRS calls both use the same network resources. The extent of the impact depends upon the number of timeslots, if any, that are reserved for exclusive use of GPRS. However, GPRS does dynamically manage channel allocation and allow a reduction in peak time signalling channel loading by sending short messages over GPRS channels instead.
RESULT: NEED FOR SMS as a complementary bearer that uses a different type of radio resource.
RESULT: NEED FOR SMS as a complementary bearer that uses a different type of radio resource.
SPEEDS MUCH LOWER IN REALITY :
Achieving the theoretical maximum GPRS data transmission speed of 172.2 kbps would require a single user taking over all eight timeslots without any error protection. Clearly, it is unlikely that a network operator will allow all timeslots to be used by a single GPRS user. Additionally, the initial GPRS terminals are expected be severely limited- supporting only one, two or three timeslots. The bandwidth available to a GPRS user will therefore be severely limited. As such, the theoretical maximum GPRS speeds should be checked against the reality of constraints in the networks and terminals. The reality is that mobile networks are always likely to have lower data transmission speeds than fixed networks.
RESULT: Relatively high mobile data speeds may not be available to individual mobile users until Enhanced Data rates for GSM Evolution (EDGE) or Universal Mobile Telephone System (3GSM) are introduced.
RESULT: Relatively high mobile data speeds may not be available to individual mobile users until Enhanced Data rates for GSM Evolution (EDGE) or Universal Mobile Telephone System (3GSM) are introduced.
SUPPORT OF GPRS MOBILE TERMINATE BY TERMINALS IS NOT ENSURED:
At the time of writing, there has been no confirmation from any handset vendors that mobile terminated GPRS calls (i.e. receipt of GPRS calls on the mobile phone) will be supported by the initial GPRS terminals. Availability or not of GPRS MT is a central question with critical impact on the GPRS business case such as application migration from other nonvoice bearers.
By originating the GPRS session, users confirm their agreement to pay for the delivery of content from that service. This origination may well be performed using a Wireless Application Protocol (WAP) session using the WAP microbrowser that will be built into GHPRS terminals. However, mobile terminated IP traffic might allow unsolicited information to reach the terminal. Internet sources originating such unsolicited content may not be chargeable. A possible worse case scenario would be that mobile users would have to pay for receiving unsolicited junk content. This is a potential reason for a mobile vendor NOT to support GPRS Mobile Terminate in their GPRS terminals.
However, there is always the possibility of unsolicited or unwanted information being communicated through any media, but that does not mean that we would wish to preclude the possibility of any kind of communication through that means altogether. A network side solution such as GGSN or charging platform policing would be preferable rather than a non-flexible limitation built into all the GPRS handsets.
When we asked Nokia about this issue, it commented: "Details of the Nokia GPRS terminals are not available at this time. It is too early to confirm whether MT will be supported in the first Nokia GPRS terminals". The company's policy is not to make details available about products before they are announced. Readers should contact the GSM Association, Mobile Lifestreams Limited and/ or the vendors directly to encourage them to incorporate support for GPRS MT in their initial terminals.
RESULT: GPRS usability and therefore business case is threatened if GPRS MT is not supported by GPRS terminals.
By originating the GPRS session, users confirm their agreement to pay for the delivery of content from that service. This origination may well be performed using a Wireless Application Protocol (WAP) session using the WAP microbrowser that will be built into GHPRS terminals. However, mobile terminated IP traffic might allow unsolicited information to reach the terminal. Internet sources originating such unsolicited content may not be chargeable. A possible worse case scenario would be that mobile users would have to pay for receiving unsolicited junk content. This is a potential reason for a mobile vendor NOT to support GPRS Mobile Terminate in their GPRS terminals.
However, there is always the possibility of unsolicited or unwanted information being communicated through any media, but that does not mean that we would wish to preclude the possibility of any kind of communication through that means altogether. A network side solution such as GGSN or charging platform policing would be preferable rather than a non-flexible limitation built into all the GPRS handsets.
When we asked Nokia about this issue, it commented: "Details of the Nokia GPRS terminals are not available at this time. It is too early to confirm whether MT will be supported in the first Nokia GPRS terminals". The company's policy is not to make details available about products before they are announced. Readers should contact the GSM Association, Mobile Lifestreams Limited and/ or the vendors directly to encourage them to incorporate support for GPRS MT in their initial terminals.
RESULT: GPRS usability and therefore business case is threatened if GPRS MT is not supported by GPRS terminals.
SUBOPTIMAL MODULATION :
GPRS is based on a modulation technique known as Gaussian minimum-shift keying (GMSK). EDGE is based on a new modulation scheme that allows a much higher bit rate across the air interface- this is called eight-phase-shift keying (8 PSK) modulation. Since 8 PSK will also be used for 3GSM, network operators will need to incorporate it at some stage to make the transition to third generation mobile phone systems.
RESULT: NEED FOR EDGE.
RESULT: NEED FOR EDGE.
TRANSIT DELAYS :
GPRS packets are sent in all different directions to reach the same destination. This opens up the potential for one or some of those packets to be lost or corrupted during the data transmission over the radio link. The GPRS standards recognize this inherent feature of wireless packet technologies and incorporate data integrity and retransmission strategies. However, the result is that potential transit delays can occur.
Because of this, applications requiring broadcast quality video may well be implemented using High Speed Circuit Switched Data (HSCSD). HSCSD is simply a Circuit Switched Data call in which a single user can take over up to four separate channels at the same time. Because of its characteristic of end to end connection between sender and recipient, transmission delays are less likely.
RESULT: NEED FOR HSCSD.
Because of this, applications requiring broadcast quality video may well be implemented using High Speed Circuit Switched Data (HSCSD). HSCSD is simply a Circuit Switched Data call in which a single user can take over up to four separate channels at the same time. Because of its characteristic of end to end connection between sender and recipient, transmission delays are less likely.
RESULT: NEED FOR HSCSD.
NO STORE AND FORWARD :
Whereas the Store and Forward Engine in the Short Message Service is the heart of the SMS Center and key feature of the SMS service, there is no storage mechanism incorporated into the GPRS standard, apart from the incorporation of interconnection links between SMS and GPRS.
RESULT: NEED FOR SMS.
RESULT: NEED FOR SMS.
Related GPRS Challenges
Following are the GPRS challenges :
1.) Billing
2.) Tariffing
3.) Customer Service
1.) Billing
2.) Tariffing
3.) Customer Service
BILLING:
GPRS is a different kind of service from those typically available on today’s mobile networks. GPRS is essentially a packet switching overlay on a circuit switching network. The GPRS specifications stipulate the minimum charging information that must be collected in the Stage 1 service description. These include destination and source addresses, usage of radio interface, usage of external Packet Data Networks, usage of the packet data protocol addresses, usage of general GPRS resources and location of the Mobile Station. Since GPRS networks break the information to be communicated down into packets, at a minimum, a GPRS network needs to be able to count packets to charging customers for the volume of packets they send and receive. Today's billing systems have difficulties handling charging for today's nonvoice services. It is unlikely that circuit switched billing systems will be able to process a large number of new variables created by GPRS.
GPRS call records are generated in the GPRS Service Nodes. The GGSN and SGSN may not be able to store charging information but this charging information needs to be processed. The incumbent billing systems are often not able to handle real time Call Detail Record flows. As such, an intermediary charging platform is a good idea to and preparing it for submission to perform billing mediation by collecting the charging information from the GPRS nodes the billing system. Packet counts are passed to a Charging Gateway that generates Call Detail Records that are sent to the billing system.
However, the crucial challenge of being able to bill for GPRS and therefore earn a return on investment in GPRS is simplified by the fact that the major GPRS infrastructure vendors all support charging functions as part of their GPRS solutions. Additionally, a wide range of other existing non-GSM packet data networks such as X.25 and Cellular Digital Packet Data (CDPD) are in place along with associated billing systems.
It may well be the case that the cost of measuring packets is greater than their value. The implication is that there will NOT be a per packet charge since there may be too many packets to warrant counting and charging for. For example, a single traffic monitoring application can generate tens of thousands of packets per day. Thus the charging gateway function is more a policing function than a charging function since network operators are likely to tariff certain amounts of GPRS traffic at a flat rate and then need to monitor whether these allocations are far exceeded.
This is not to say that we will end up with the free Internet Service Provider model that has become established on the fixed Internet in which users pay no fixed monthly charge and network operators rely on advertising sales on mobile portal sites to make money. There is a premium for mobility and there is frankly a shortage of mobile bandwidth that limits the extent to which that bandwidth is viewed as a commodity. And given the additional customer care and billing complexity associated with mobile
Internet and nonvoice services, network operators would be ill advised to reduce their prices in such a way as to devalue the perceived value of mobility.
GPRS call records are generated in the GPRS Service Nodes. The GGSN and SGSN may not be able to store charging information but this charging information needs to be processed. The incumbent billing systems are often not able to handle real time Call Detail Record flows. As such, an intermediary charging platform is a good idea to and preparing it for submission to perform billing mediation by collecting the charging information from the GPRS nodes the billing system. Packet counts are passed to a Charging Gateway that generates Call Detail Records that are sent to the billing system.
However, the crucial challenge of being able to bill for GPRS and therefore earn a return on investment in GPRS is simplified by the fact that the major GPRS infrastructure vendors all support charging functions as part of their GPRS solutions. Additionally, a wide range of other existing non-GSM packet data networks such as X.25 and Cellular Digital Packet Data (CDPD) are in place along with associated billing systems.
It may well be the case that the cost of measuring packets is greater than their value. The implication is that there will NOT be a per packet charge since there may be too many packets to warrant counting and charging for. For example, a single traffic monitoring application can generate tens of thousands of packets per day. Thus the charging gateway function is more a policing function than a charging function since network operators are likely to tariff certain amounts of GPRS traffic at a flat rate and then need to monitor whether these allocations are far exceeded.
This is not to say that we will end up with the free Internet Service Provider model that has become established on the fixed Internet in which users pay no fixed monthly charge and network operators rely on advertising sales on mobile portal sites to make money. There is a premium for mobility and there is frankly a shortage of mobile bandwidth that limits the extent to which that bandwidth is viewed as a commodity. And given the additional customer care and billing complexity associated with mobile
Internet and nonvoice services, network operators would be ill advised to reduce their prices in such a way as to devalue the perceived value of mobility.
TARIFFING:
Decisions on charging for GPRS by packet or simply a flat monthly fee are contentious but need to be made. Charging different packets at different rates can make things complicated for the user, whilst flat rates favor heavy users more than occasional ones.
We believe that the optimal GPRS pricing model will be based on two variables- time and packet. Network operators should levy a nominal per packet charge during peak times plus a flat rate, no per packet charge during non peak times. Time and packet related charging will encourage applications such as remote monitoring, meter reading and chat to use GPRS overnight when spare network capacity is available. Simultaneously, a nominal per packet charge during the day will help to allocate scarce radio resources and charge radio heavy applications such as file and image transfer more than applications with lower data intensity. It has the advantage that it will automatically adjust customer charging according to their application usage.
As such the optimal charging model could well be a flat rate charge during off-peak times along with a per packet charge during peak times.
We believe that the optimal GPRS pricing model will be based on two variables- time and packet. Network operators should levy a nominal per packet charge during peak times plus a flat rate, no per packet charge during non peak times. Time and packet related charging will encourage applications such as remote monitoring, meter reading and chat to use GPRS overnight when spare network capacity is available. Simultaneously, a nominal per packet charge during the day will help to allocate scarce radio resources and charge radio heavy applications such as file and image transfer more than applications with lower data intensity. It has the advantage that it will automatically adjust customer charging according to their application usage.
As such the optimal charging model could well be a flat rate charge during off-peak times along with a per packet charge during peak times.
CUSTOMER SERVICE :
Value-added network services such as mobile data, mobile Internet and unified messaging all generate certain specific customer problems and requirements, thereby requiring customer service personnel to be aware of these issues and know how to solve them.
Nonvoice services are surprisingly complex- involving unique configurations of phone types, data cards, handheld computers, subscriptions, operating systems, Internet service providers and so on. Some network operators require customers to opt into certain value added services rather than including them as part of the core subscription- necessitating a customer service process. It is even possible to write a 350 page book about the SHORT message service (it is called "YES2SMS")!
In theory, the need for dedicated customer service for Circuit Switched Data, SMS and other nonvoice mobile services will decrease in the future as terminals and services become easier to use and as the services themselves are used more widely for customer service purposes.
The reality in the short and medium term is that the need for customer support for value-added services will increase not decrease as awareness of services and their usage increases, and as new services and terminals come onto the marketplace.
Rather than keeping everything in-house or outsourcing everything, we are a proponent of an approach that keeps first line support and customer contact in-house, whilst outsourcing the difficult specific customer service problems arising from connectivity issues and so on. In this way, the network operator is aware of and in control of the kinds of questions and problems its customers are asking.
It is well worth incurring the cost to get the customer aware, educated and initially set up with data services, because, for example, once the PC data card has been successfully connected to the laptop to the Internet software and so on, the same configuration can be repeatedly used. The one-off customer requirement leads to ongoing usage.
Nonvoice services are surprisingly complex- involving unique configurations of phone types, data cards, handheld computers, subscriptions, operating systems, Internet service providers and so on. Some network operators require customers to opt into certain value added services rather than including them as part of the core subscription- necessitating a customer service process. It is even possible to write a 350 page book about the SHORT message service (it is called "YES2SMS")!
In theory, the need for dedicated customer service for Circuit Switched Data, SMS and other nonvoice mobile services will decrease in the future as terminals and services become easier to use and as the services themselves are used more widely for customer service purposes.
The reality in the short and medium term is that the need for customer support for value-added services will increase not decrease as awareness of services and their usage increases, and as new services and terminals come onto the marketplace.
Rather than keeping everything in-house or outsourcing everything, we are a proponent of an approach that keeps first line support and customer contact in-house, whilst outsourcing the difficult specific customer service problems arising from connectivity issues and so on. In this way, the network operator is aware of and in control of the kinds of questions and problems its customers are asking.
It is well worth incurring the cost to get the customer aware, educated and initially set up with data services, because, for example, once the PC data card has been successfully connected to the laptop to the Internet software and so on, the same configuration can be repeatedly used. The one-off customer requirement leads to ongoing usage.
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