Prepaid


Contents

  1. 1 Prepaid Account
    1. 1.1 Account Parameters
  2. 2 Prepaid Call
    1. 2.1 Announcement of Available Minute
    2. 2.2 Mid Call Balance Control
    3. 2.3 Total Charge at End of Call
  3. 3 Prepaid Pass Through
  4. 4 Auto Account Creation with Prepaid Card
  5. 5 Recharge Procedures
  6. 6 Prepaid Card Number


Prepaid Account

Account Parameters

Parameter Name
 Database Field
 type Default Descriptions
User account_user
varchar <NULL> Account User
Domain
account_domain
varchar <NULL> Account Domain
Status
account_status
'locked' or 'active'
'active'
Account Status
1st Use From
 valid_from
date
 0000-00-00Date from which 1st Use is allowed
1st Use To
 		valid_to
date 0000-00-00Date to which 1st Use is allowed
Use Period
 		valid_period
varchar '1 year'
Period from 1st Use that account stay valid
Date 1st Use
 date_1st_use
date 0000-00-00Date of 1st Use
Set upon 1st Use
Date Last Use
date_last_use
date0000-00-00Date of Last Use
Updated upon each Use
Use Expire
 		date_expire
date0000-00-00Date to which account expire
Set upon 1st Use as <Date 1 Use> + <Valid Period>
Original Balance
orig_balance
double
0
Balance when the account is created
Balance
balance
double
0
Current balance
Rate Plan
rate_plan
varchar
<NULL>
Rate Plan for this Account
Service Plan
service_plan
varchar
<NULL>
Service Plan for this Account
Last Charge Date
srv_charge_last
date
0000-00-00Date of last Service Charge to this Account
Next Charge Date
srv_charge_next
date
0000-00-00Date of next Service Charge to this Account
Next Reset Date
reset_next
varchar
'never'
Next date to reset the Balance back to the <Original Balance>


Prepaid Call

Announcement of Available Minute

Announcement of Available Minute at the beginning of a Prepaid Call has the following steps
  1. Caller enter the Destination number
  2. NMS lookup Dial Plan, Dial Policy and Route Table to form the destination SIP URI
  3. NMS send Rate Quote request with the Caller's Account, From-URI and To-URI to the NAS
  4. NAS lookup the Account Balance and Rate Table entry to calculate the available minute and return the result to the NMS
  5. If the Rate Quote result is OK, the NMS announce the available minute to the caller
Calculation of the Available Minute by the NAS is as follow :
 
[Available Second] = ( [Account Balance] - [Extra Charge from Rate Entry] ) * 60 / [Rate per Minute] + 0.5;

if ( [Available Second] > [Max Talk Time])
     [Available Second] = [Max Talk Time];

[Available Minute] = truncate( [Available Second] / 60 );

Mid Call Balance Control

At configurable interval during an active Prepaid Call :
  1. NMS send Rate Continue request to the NAS
  2. NAS update the calculation of the incurred charge, compare against the Caller's Account Balance to calculate the Remaining Talk Time and return the result to the NMS
  3. If the Remaining Talk Time reach the Whisper Threshold, the Remaining Talk Time will be whispered to the Caller
  4. If the Remaining Talk Time is zero, the NMS will disconnect the call

Calculation for mid call balance control:
 
[Usage Charge] = [Duration] * [Rate] ;

[Incurred Charge] = [Usage Charge];

if ( [Actual Duration] > [Long Call Duration Threshold] )
    [Incurred Charge] += [Long Call Charge];

if ( ( [Actual Duration] - [Long Call Duration Threshold] ) > [Long Call Increment] * N )
    [Incurred Charge] += [Long Call Charge] * N;


Total Charge at End of Call

Calculation of Total Charge at End of Call
 
[Usage Charge] = [Duration] * [Rate];

[Total Charge before Tax] = [Usage Charge];

if ( [Actual Duration] > [Long Call Duration Threshold] )
    [Total Charge before Tax] += [Long Call Charge];

if ( ( [Actual Duration] - [Long Call Duration Threshold] ) > [Long Call Increment] * N )
    [Total Charge before Tax] += [Long Call Charge] * N;

if ( [Actual Duration] > [Disconnect Charge Duration Threshold] )
    [Total Charge before Tax] += [Disconnect Charge];

[Total Charge] = [Total Charge before Tax] * ( 1 + [Tax Rate] );



Prepaid Pass Through

  • Prepaid Pass Through is a Responder Application in the NMS.
  • Require no Subscriber Account in the NMS
  • The Caller is prompted for Account PIN
  • NMS queries AccountBalance from the NAS
  • If the Account PIN doesn't exist in the NAS's Account Table, the NAS will apply the "Auto Account Creation" procedure described below
  • NMS admit the caller to made upon valid Balance and Expiration information returned from NAS

Auto Account Creation with Prepaid Card

When processing an AccountBalance Request for a non-existing account, the NAS will search its Prepaid Card table, matching the Account Number against the Prepaid Card Activation Code. If there is a match and that the associated Prepaid Card is valid, un-used and not-locked :

  1. A new NAS account will be created with the Account Number equal to the Prepaid Card Activation Code.
  2. The full value of the Prepaid Card will be transferred to the newly Created Account.
  3. The Rate Plan, Service Plan, Service Charge Day of Month and Account Balance Reset Day of Month will be defined by the Prepaid card entry
  4. The "Date 1st Use" of the Created Account will be set to current Date
  5. The "Use Expire" of the Created Account will be set to current Date + "Use Period" of the Prepaid Card
  6. The Prepaid Card will be marked as used by the Created Account
  7. A Service Record entry with "Category"=="Create Account" will be inserted to registered the time of the account creation and the amount transferred from the Prepaid Card to the Created Account.
  8. The Balance and Expiration information will be returned in the Response to the AccountBalance Request


Recharge Procedures

  1. Validate Domain and Account
  2. Check for existence and not locked
    • Current Date is before the "Use Expire" of the Recharging Account
  3. Validate Prepaid Card
    • Activation Code exist
    • Current Date is within "Valid From" to "Valid To" of the Prepaid card
    • Prepaid Card is Not Locked
    • Prepaid Card is Not Used
  4. The full value of the Prepaid Card will be transferred to the Recharging Account.
  5. The "Use Expire" of the Recharged Account will be extended to current Date + "Use Period" of the Prepaid Card
  6. The Prepaid Card will be marked as used by the Recharged Account
  7. A Service Record entry with "Category"=="Recharge Account" will be inserted to registered the date of the account recharge and the amount transferred from the Prepaid Card to the Recharged Account.

Prepaid Card Number

  • Unique per Domain
  • 10 to 16-digit Activation Code
  • 5 to 9-digit Serial Number
    • Upto 100K to 1-billion Recharge Card per domain
  • 5 to 7-digit Cryptographic Hash
    • 100K to 10-million combinations for each code against Brute Force attack


Code Length # S/N Digit # Hash Digit # Card
16 9 7 1 billion
15 8 7 100 million
14 7 7 10 million
13 6 7 1 million
12 6 7 1 million
11 6 5 1 million
10 5 5 100K

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