This document summarizes key points about wireless roaming networks. It defines home and visiting networks and explains the call processing and billing when a user roams. International dialing requirements are also outlined. Roaming charges can be complicated involving fees for the home, visiting, and international networks. Regulations have attempted to curb high intra-EU roaming fees but controlling fees internationally is difficult without government agreements. The document recommends educating roaming users and ways for carriers to help customers avoid unexpected roaming charges. Alternatives like local SIMs, VoIP, and WiFi are also presented.

1. Seminar with TCI
June 16, 2011
Supot Tiarawut
TRIDI

2. Roaming in Wireless Networks, Shahid K. Siddiqui, McGraw-Hill 2

3.  PLMN – Public Land Mobile Network = a
mobile network = wireless equivalent of
PSTN
 VPLMN – Visiting PLMN
 HPLMN – Home PLMN
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4. Roaming in Wireless Networks, Shahid K. Siddiqui, McGraw-Hill 4

5.  Once roamer is allowed to make outgoing
calls by HPLMN, all the calls will be processed
by VPLMN. HPLMN plays no further role in
call processing.
 Roamer needs to key completed international
numbers, +<CC><NC><MSISDN>
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6. Roaming in Wireless Networks, Shahid K. Siddiqui, McGraw-Hill 6

7. Roaming in Wireless Networks, Shahid K. Siddiqui, McGraw-Hill 7

8. Roaming in Wireless Networks, Shahid K. Siddiqui, McGraw-Hill 8

9.  More complicated
 Real time credit deduct
 Charging signals between visiting network
and home network
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10.  A charge to roamer goes to
 Home network
 International network
 Visiting network
 Wholesale price charged by visiting network
is usually high resulting in high roaming fee.
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11.  REGULATION (EC) No 544/2009
 Control ceiling of wholesale charge by visiting
networks
 Control ceiling of retail charge by home
networks
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12.  EU can do it because EU government has
control over European Countries.
 THAILAND: we don’t have control over
networks of other countries
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13.  High charges
 High roaming charges everywhere
 EU started regulations to curb intra-EU charges
 Un-intentional charging
 Due to increasing uses of smart phones
 Roaming without data-off
 Roaming into WiFi but turning on Data Roaming
un-intentionally
▪ Misunderstanding of WiFi signal as connected while
requiring network key or passwords to log on
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14.  Better educate roaming users!
 Study roaming plans extensively
 Choose packages according to intended period of
stay and pattern of usages: volume-based or
duration-based for data
 Remember network setup
 Know operating procedure of the handsets well
and set up prior to landing
 Select the right network for connections
 Make sure the procedures completed.
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15.  What home providers can do to help…
 Should not charge unless and until the roaming
customers accepts the provision of the service.
 Should provide personalized tariff information
 Should give examples for data roaming
applications indicating approximate size
 Should give notification when limit approached,
and provide options to choose if continuation of
services are specifically requested
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16.  Local SIMs
 VoIP
 WiFi
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17. It might be better to stay off the net for a while!
Thank you!!
Email: supot@tridi.ntc.or.th
Twitter: @supott
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