Method for predictive pacing of calls in a calling system

• US 4,881,261 A
• Filed: 06/29/1988
• Issued: 11/14/1989
• Est. Priority Date: 06/29/1988
• Status: Expired due to Term

• Current Assignee: Firstpoint Contact Technologies, LLC (Alvaria Incorporated)
• Original Assignee: Rockwell International Corporation
• Inventors: Oliphant, Jean R., Workman, Harold W., Shah, Jasvantrai C.
• Primary Examiner(s): Dwyer, James L.
• Application Number:
  US07/245,097
• Time in Patent Office: 503 Days
• Field of Search: 379/92, 379/269, 379/265, 379/266, 379/309, 379/215
• US Class Current: 379/266.08
• CPC Class Codes: H04M 3/5158 in combination with automated outdialling systems devices for signalling identity of wanted subscriber H04M1/26
• CPC Class Codes: H04M 3/5175 Call or contact centers supervision arrangements
• CPC Class Codes: H04M 3/523 with call distribution or queueing
• CPC Class Codes: H04M 3/5238 with waiting time or load prediction arrangements
• CPC Class Codes: H04Q 3/625 Arrangements in the private branch exchange
• CPC Class Codes: Y10S 379/904 Auto-calling

Abstract

A system having calls substantially selected and dialed to customers at such a paced rate that the system will keep a group of agents at full occupancy with calls on which the system has detected voice answer. As the size of the agent group changes, this predictive pacing is adjusted so that answered calls do not have to be delayed while waiting for an available agent or agents do not have to wait for calls to become available.

Claims

1. A method of automatically selecting and dialing customer telephone at a paced rate and keeping a plurality of agent stations at full occupancy, comprising:

providing a database containing telephone numbers to be called;

providing a computer for controlling the pacing of telephone numbers to be called connected to said database;

providing an automatic call distribution system for dialing the telephone numbers and establishing connection to the customer telephone and connected to said computer;

providing a plurality of agent stations connected to said computer and to said automatic call distribution system;

determining the maximum number, K, of calls to be in progress at any time by calculating the maximum number, K, such that an average number, Q, of calls waiting in a queue does not exceed a selected delay, DMAX;

initiating a new call only when there are less than K calls existing; and

for a set up state determining the number, NQ, of calls waiting in queue from the maximum permissible number, QMAX, of calls waiting in queue less a known number, NS, of calls dialed and waiting a response;

determining the probability P(NS) of having exactly NS calls in the set-up state from

space="preserve" listing-type="equation">P(NS)=e.sup.(-R*S) (R*S).sup.NS /NS

where R is the rate of connection to agents and S is the average call set-up time, setting QMAX equal to a large value;

determining the average number, Q, of calls waiting in queue from ##EQU1## determining the average delay D, in queue from D=Q/R;

decreasing QMAX and recalculating Q until D exceeds DMAX; and

determining the value, K, from K=QMAX+M.

2. A method of automatically selecting and dialing customer telephones at a paced rate and keeping a plurality of agent stations at full occupancy, comprising:

providing a database containing telephone numbers to be called;

providing a computer for controlling the pacing of telephone numbers to be called connected to said database;

providing an automatic call distribution system for dialing the telephone numbers and establishing connection to the customer telephone and connected to said computer;

providing a plurality of agent stations connected to said computer and to said automatic call distribution system;

determining the maximum number, K, of calls to be in progress at any one time by calculating the maximum number, K, such that an average number, Q, of calls waiting in a queue does not exceed a selected delay, DMAX;

initiating a new call only when there are less than K calls existing; and

for a set-up state determining the number, NQ, of calls waiting in queue from the maximum permissible number, QMAX, of calls waiting in queue less a known number, NS, of calls dialed and waiting a response;

determining the probability P (NS) of having exactly NS calls in the set-up state as a function of a rate R of connection to agents and of an average call set-up time S;

determining the average number, Q, of calls waiting in queue as a function of the rate R, the set-up time S, the maximum number K and a selected large value QMAX;

determining the average delay D, in queue from D=Q/R;

decreasing QMAX and recalculating Q until D exceeds DMAX; and

determining the value, K, from K=QMAX+M.

3. A method of automatically selecting and dialing customer telephones at a paced rate and keeping a plurality of agent stations at full occupancy, comprising:

providing a database containing telephone numbers to be called;

providing a computer for controlling the pacing of telephone numbers to be called connected to said database;

providing an automatic call distribution system for dialing the telephone numbers and establishing connection to the customer telephone and connected to said computer;

providing a plurality of agent stations connected to said computer and to said automatic call distribution system;

providing a plurality of queues each with assigned agent stations for servers to service calls;

providing sets of dynamic variables which are measurements of current call performance for each queue, average server hold time, average call set-up time, rate of connection of calls to servers, and average number of calls in the delay queue;

providing a set of dynamic variables which are the current number of agents signed-in at agent stations to serve each queue;

determining for each queue the maximum number, K, of calls to be in progress at any one time based upon an iterative algorithm which uses the dynamic variables and calculated probabilities for the numbers of calls in various call set-up states; and

initiating a new call only when there are less than K calls existing.

4. The method described in claim 3, wherein the method further comprises calculating the maximum number, K, such that an average number, Q of calls waiting in a queue does not exceed a selected delay, DMAX.

5. The method described in claim 4, wherein the method further comprises for the set-up state determining the number, NQ, of calls waiting in queue from the maximum permissible number, QMAX, of calls waiting in queue less a known number, NS, of calls dialed and waiting a response;

determining the probability P(NS) of having exactly NS calls in the set-up state from

space="preserve" listing-type="equation">P(NS)=e.sup.(-R*S) (R*S).sup.NS /NS

where R is the rate of connection to agents and S is the average call set-up time, setting QMAX equation to a large value;

determining the average number, Q, of calls waiting in queue from ##EQU2## determining the average delay D, in queue from D=Q/R;

decreasing QMAX and recalculating Q until D exceeds DMAX; and

determining the value, K, from K=QMAX+M.