telecommunications-expert

Telecommunications Expert

Expert guidance for telecommunications systems, network management, billing systems, 5G networks, SDN/NFV, and telecom infrastructure management.

Core Concepts

Telecommunications Systems

• Operations Support Systems (OSS)
• Business Support Systems (BSS)
• Network Management Systems (NMS)
• Service Assurance
• Inventory Management
• Provisioning systems
• Customer care platforms

Network Technologies

• 5G/4G/LTE networks
• Fiber optic networks
• Software-Defined Networking (SDN)
• Network Functions Virtualization (NFV)
• Edge computing
• IoT connectivity
• Satellite communications

Standards and Protocols

• 3GPP standards
• TM Forum Frameworx
• ETSI specifications
• ITU-T recommendations
• SIP (Session Initiation Protocol)
• Diameter protocol
• SNMP for network management

Billing System

from decimal import Decimal

@dataclass
class Subscriber:
    """Telecom subscriber"""
    subscriber_id: str
    account_number: str
    name: str
    phone_number: str
    email: str
    address: dict
    plan_id: str
    status: str  # 'active', 'suspended', 'terminated'
    activation_date: datetime

@dataclass
class ServicePlan:
    """Service plan/package"""
    plan_id: str
    name: str
    description: str
    monthly_fee: Decimal
    data_allowance_gb: float
    voice_minutes: int
    sms_count: int
    overage_rates: dict

@dataclass
class UsageRecord:
    """Usage record for billing"""
    record_id: str
    subscriber_id: str
    usage_type: str  # 'voice', 'sms', 'data'
    timestamp: datetime
    quantity: float
    unit: str
    destination: Optional[str]
    charged: bool

class BillingSystem:
    """Telecom billing and charging system"""

    def __init__(self):
        self.subscribers = {}
        self.service_plans = {}
        self.usage_records = []
        self.invoices = []

    def process_usage(self, usage: UsageRecord) -> dict:
        """Process usage record for charging"""
        subscriber = self.subscribers.get(usage.subscriber_id)
        if not subscriber:
            return {'error': 'Subscriber not found'}

        if subscriber.status != 'active':
            return {'error': 'Subscriber not active'}

        plan = self.service_plans.get(subscriber.plan_id)
        if not plan:
            return {'error': 'Service plan not found'}

        # Check if usage is within plan allowance
        current_usage = self._get_current_month_usage(usage.subscriber_id, usage.usage_type)

        charge = Decimal('0')

        if usage.usage_type == 'data':
            if current_usage > plan.data_allowance_gb:
                # Overage charges
                overage_gb = usage.quantity
                charge = Decimal(str(overage_gb)) * plan.overage_rates['data_per_gb']

        elif usage.usage_type == 'voice':
            if current_usage > plan.voice_minutes:
                # Overage charges
                overage_minutes = usage.quantity
                charge = Decimal(str(overage_minutes)) * plan.overage_rates['voice_per_minute']

        elif usage.usage_type == 'sms':
            if current_usage > plan.sms_count:
                # Overage charges
                overage_sms = usage.quantity
                charge = Decimal(str(overage_sms)) * plan.overage_rates['sms_per_message']

        usage.charged = True
        self.usage_records.append(usage)

        return {
            'subscriber_id': usage.subscriber_id,
            'usage_type': usage.usage_type,
            'quantity': usage.quantity,
            'charge': float(charge),
            'within_allowance': charge == 0
        }

    def generate_invoice(self, subscriber_id: str, billing_period: tuple) -> dict:
        """Generate monthly invoice"""
        subscriber = self.subscribers.get(subscriber_id)
        if not subscriber:
            return {'error': 'Subscriber not found'}

        plan = self.service_plans.get(subscriber.plan_id)
        start_date, end_date = billing_period

        # Base charges
        monthly_fee = plan.monthly_fee

        # Usage charges
        period_usage = [
            u for u in self.usage_records
            if u.subscriber_id == subscriber_id and
            start_date <= u.timestamp <= end_date
        ]

        usage_charges = self._calculate_usage_charges(period_usage, plan)

        # Taxes (simplified)
        subtotal = monthly_fee + usage_charges['total']
        tax_rate = Decimal('0.10')  # 10%
        taxes = subtotal * tax_rate

        total = subtotal + taxes

        invoice = {
            'invoice_id': self._generate_invoice_id(),
            'subscriber_id': subscriber_id,
            'account_number': subscriber.account_number,
            'billing_period': {
                'start': start_date.isoformat(),
                'end': end_date.isoformat()
            },
            'charges': {
                'monthly_fee': float(monthly_fee),
                'data_charges': float(usage_charges['data']),
                'voice_charges': float(usage_charges['voice']),
                'sms_charges': float(usage_charges['sms']),
                'other_charges': float(usage_charges['other'])
            },
            'subtotal': float(subtotal),
            'taxes': float(taxes),
            'total': float(total),
            'due_date': (end_date + timedelta(days=15)).isoformat()
        }

        self.invoices.append(invoice)

        return invoice

    def _get_current_month_usage(self, subscriber_id: str, usage_type: str) -> float:
        """Get current month usage for subscriber"""
        current_month_start = datetime.now().replace(day=1, hour=0, minute=0, second=0)

        usage = [
            u for u in self.usage_records
            if u.subscriber_id == subscriber_id and
            u.usage_type == usage_type and
            u.timestamp >= current_month_start
        ]

        total = sum(u.quantity for u in usage)
        return total

    def _calculate_usage_charges(self,
                                usage_records: List[UsageRecord],
                                plan: ServicePlan) -> dict:
        """Calculate usage charges"""
        charges = {
            'data': Decimal('0'),
            'voice': Decimal('0'),
            'sms': Decimal('0'),
            'other': Decimal('0'),
            'total': Decimal('0')
        }

        # Group usage by type
        data_usage = sum(u.quantity for u in usage_records if u.usage_type == 'data')
        voice_usage = sum(u.quantity for u in usage_records if u.usage_type == 'voice')
        sms_usage = sum(u.quantity for u in usage_records if u.usage_type == 'sms')

        # Calculate overage charges
        if data_usage > plan.data_allowance_gb:
            overage = data_usage - plan.data_allowance_gb
            charges['data'] = Decimal(str(overage)) * plan.overage_rates['data_per_gb']

        if voice_usage > plan.voice_minutes:
            overage = voice_usage - plan.voice_minutes
            charges['voice'] = Decimal(str(overage)) * plan.overage_rates['voice_per_minute']

        if sms_usage > plan.sms_count:
            overage = sms_usage - plan.sms_count
            charges['sms'] = Decimal(str(overage)) * plan.overage_rates['sms_per_message']

        charges['total'] = sum([charges['data'], charges['voice'], charges['sms'], charges['other']])

        return charges

    def _generate_invoice_id(self) -> str:
        import uuid
        return f"INV-{uuid.uuid4().hex[:10].upper()}"