dioscouri/omnipay-cybersource issue

[amitjhachetutesting chetu]

Array
(
    [/payment/authorize_results] => 
    [utf8] => ✓
    [req_card_number] => xxxxxxxxx2222
    [req_locale] => en
    [signature] => j+kpTPp5Wwglg1d1ADE8YpGpIUWw6moLBun7RZQtjlg=
    [req_bill_to_surname] => Tets
    [req_bill_to_address_city] => New York
    [req_card_expiry_date] => 01-2029
    [req_bill_to_address_postal_code] => 10001
    [reason_code] => 101
    [req_bill_to_forename] => Naresh
    [req_payment_method] => card
    [req_amount] => 10.00
    [req_bill_to_email] => joes...@example.com
    [req_currency] => USD
    [req_card_type] => 001
    [decision] => ERROR
    [message] => Request parameters are invalid or missing
    [signed_field_names] => decision,req_access_key,req_profile_id,req_transaction_uuid,req_transaction_type,req_amount,req_currency,req_locale,req_payment_method,req_bill_to_forename,req_bill_to_surname,req_bill_to_email,req_bill_to_address_line1,req_bill_to_address_city,req_bill_to_address_state,req_bill_to_address_country,req_bill_to_address_postal_code,req_card_number,req_card_type,req_card_expiry_date,required_fields,reason_code,message,signed_field_names,signed_date_time
    [req_transaction_uuid] => 5da6ffe1b3b1a
    [required_fields] => reference_number
    [req_bill_to_address_country] => US
    [req_transaction_type] => sale
    [req_access_key] => 4195c8229b2939c1bf4180187e42eb2a
    [req_profile_id] => E5A1978D-7C1F-4C09-92C0-C437879CB312
    [req_bill_to_address_state] => NY
    [signed_date_time] => 2019-10-16T11:32:52Z
    [req_bill_to_address_line1] => New York
)

I am using cybersource with omnipay and getting above response and found that reference_number is required.
How can I pass this reference_number. please assist me.