|
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.
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 UMTS, network operators will need to incorporate it at some
stage to make the transition to third generation mobile phone systems.
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 recognise 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.
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.
|
