CS1: Wireless Communication and Mobile Programming Wireless Technologies: Short Message Service (SMS) Dr. Khaled Mahmud Laurentian University International Global Experience Program Summer–2016

Agenda Short Message Service (SMS) SMS Architecture Types of Messages Value Added Services (VAS) using SMS Architecture Short Message Peer to Peer (SMPP) Using SMS as bearer (c) Khaled Mahmud

Reference Chapter 6 [TEL] Web references (c) Khaled Mahmud

Overlay of Mobile Data in GSM The data service make use of the followings of a GSM system Spectrum allocated to other service MAC frames Air interface Short Message Service (SMS) Make use of free time slots within the signaling channels General Packet Radio Service (GPRS) Make use of free time slots within the TCH (Traffic channel of GSM) Amount of new infrastructure is reduced to bare minimum Most of the extra components required are implemented in software Cheap Easy to deploy (c) Khaled Mahmud

Short Message Service (SMS) Developed as part of GSM phase 2 specs Alphanumeric messages up to 160 characters gets mapped into 140 bytes Utilizes the logical channels of the GSM system intelligently Requires an additional SMS Center (SMSC) Maintenance and transmission Sorting and routing (c) Khaled Mahmud

Cell Broadcast SMS The message is transmitted to all MSs that are active in a cell and subscribes to the service Unconfirmed one way message used for Weather forecasts Stock quotes etc. A cell broadcast entity and a cell broadcast center broadcast to multiple BSCs for delivery The broadcast contains data and identities of the MSs that are to receive this data Employs the Broadcast Channel for this (c) Khaled Mahmud

Point to Point (PTP) SMS An MS can send message to another MS If the MS is in idle mode MS has to establish a connection to the network similar to a normal call set up (for MS originated SMS) or The MS has to be paged and a connection needs to be set up between the network in a manner similar to a normal call set up (c) Khaled Mahmud

Mobile Originated SMS SM (short message) originating from the MS reaches MSC A dedicated function in the MSC called SMS interworking MSC (SMS-IWMSC) forwards it to the SMSC using the global SMS ID SMS-IWMSC MSC VLR SMSC (c) Khaled Mahmud

Mobile Terminated SMS SM is forwarded from the SMSC to the SMS gateway MSC (SMS-GMSC) function of the MSC The routing information is obtained from the HLR The MSC/VLR pages the MS VLR MSC SMSC SMS-GMSC HLR (c) Khaled Mahmud

Overall SMS Architecture SMSC (SC) HLR SMS-GMSC SMS-IWMSC VLR MSC MS1 MS2 Receiver's home network Sender's home network Serving network SM MO SM MT 1 3 2 4 5 7 12 8 9 10 11 (c) Khaled Mahmud

Misc. Information on SMS SM is transmitted through the GSM infrastructure using SS-7 SM can have Specified priority level Future delivery time Acknowledgement of message receipt Failure can occur if there is change of state of the MS when the SM is in transit (c) Khaled Mahmud

Value Added Service (VAS) Supplementary services, but adds value to the total service offering Stimulates incremental demand for the core service Creates revenue generation potential Sometimes can be stand-alone Can a be an add-on to the basic service, usually sold at a premium price (c) Khaled Mahmud

VAS Through SMS SMS can be bearer for VAS SMS may carry Static information: Less update necessary e.g. restaurant guide Dynamic information: Daily or more frequent update necessary e.g. daily horoscope Real-time information: Almost real-time update necessary e.g. Live cricket update (c) Khaled Mahmud

VAS over SMS Examples News/stock quote service Session-based chat Twitter Email through SMS Health-care service Micro-payment service (c) Khaled Mahmud

Architecture for VAS over SMS MSC BSC BTS SMSC SME/ SMS gateway Internet Content Server Data store Enterprise content Mass market content Content update SME: Short Message Entity (c) Khaled Mahmud

Short Message Entity (SME) Makes connection between enterprise origin server and SMSC SMS gateway for the enterprise Also called External SME or ESME Interface between SMSC and SME or SME and enterprise server is not defined in GMS Between SMSC and SME or ESME: SMPP (short message peer to peer) is used mostly Between SME and content server: Usually HTTP/TCP based protocol is used (e.g. SOAP) (c) Khaled Mahmud

Communication Between SMSC and SME ESMEs SMSC SMPP WAP Proxy server Mobile NW SMPP VMS SMPP Paging (c) Khaled Mahmud

Lookout for SMS Scam :Normal SMS Operation (c) Khaled Mahmud https://blog.lookout.com/blog/2012/10/03/avoid-premium-sms-scams/

Lookout for SMS Scam :Fraud Operation (c) Khaled Mahmud