vlcsim.controller.connection.Connection

class vlcsim.controller.connection.Connection(id: int, receiver: Receiver, time: float)[source]

Bases: object

Represents a data transmission connection in VLC simulation.

Connection objects encapsulate all information about a data transmission session between a receiver device and an access point (AP). Each connection tracks its allocation status, assigned time slices, capacity requirements, and timing information.

The Connection class manages:

Unique identification and association with receiver and AP
Frame/slice allocation in TDM scheduling
Capacity requirements and SNR tracking
Connection timing (arrival, goal time, completion)
Allocation status (allocated, waiting, refused)

All attributes are private and accessed via properties.

Example

Creating a connection:

receiver = Receiver(x=5.0, y=5.0, z=0.85, aDet=1e-4, ts=0.1,
                  index=1.5, fov=60.0)
connection = Connection(id=0, receiver=receiver, time=0.0)
connection.capacityRequired = 1e6  # 1 Mbps

# Assign to access point
connection.AP = vled
connection.assignFrameSlice(frame=0, slice=3)

__init__(id: int, receiver: Receiver, time: float) → None[source]

Initialize a Connection object.

Creates a new connection with specified ID, receiver, and arrival time. The connection is initially marked as allocated but not yet assigned to an AP.

Parameters:

id – Connection unique identifier (non-negative integer)
receiver – Receiver device for this connection
time – Connection arrival time in seconds (non-negative)

Raises:

ValueError – If id or time is negative

Example:

receiver = Receiver(5.0, 5.0, 0.85, 1e-4, 0.1, 1.5, 60.0)
conn = Connection(id=1, receiver=receiver, time=10.5)

Methods

`__init__`(id, receiver, time)	Initialize a Connection object.
`assignFrameSlice`(frame, slice)	Assign a specific frame and slice to this connection.
`getNextTime`()	Get the next transmission start time for this connection.
`insertTime`(time)	Insert a transmission time into the scheduled times queue.
`nextSliceInAPWhenArriving`(ap)	Determine the next available slice position when connection arrives.
`numberOfSlicesNeeded`(capacityRequired, ...)	Calculate the number of TDM slices needed for this connection.

Attributes

`AP`	Get the Access Point assigned to this connection.
`allocated`	Check if this connection has been allocated.
`capacityRequired`	Get the capacity required for this connection.
`frameSlice`	Get the list of frame/slice assignments for this connection.
`goalTime`	Get the goal time for this connection.
`id`	Get the unique identifier of this connection.
`receiver`	Get the receiver associated with this connection.
`snr`	Get the Signal-to-Noise Ratio for this connection.
`time`	Get the arrival time of this connection.

property AP: AccessPoint | None

Get the Access Point assigned to this connection.

Returns:: Access Point used by this connection, or None if not assigned
Return type:: AccessPoint or None

property allocated: bool

Check if this connection has been allocated.

Returns:: True if connection was allocated, False otherwise
Return type:: bool

assignFrameSlice(frame: int, slice: int)[source]

Assign a specific frame and slice to this connection.

Adds a [frame, slice] pair to this connection’s TDM allocation.

Parameters:

frame – Frame number to assign
slice – Slice number within the frame

Example:

connection.assignFrameSlice(frame=0, slice=3)
connection.assignFrameSlice(frame=1, slice=0)

property capacityRequired: float | None

Get the capacity required for this connection.

Returns:: Required capacity in bits per second (bps), or None if not set
Return type:: float or None

property frameSlice: list[list[int]]

Get the list of frame/slice assignments for this connection.

Returns:

List of [frame, slice] pairs that this connection will use: in TDM scheduling

Return type:

list[list[int]]

Example:

>>> connection.frameSlice
[[0, 3], [0, 7], [1, 2]]

getNextTime() → float[source]

Get the next transmission start time for this connection.

Retrieves and removes the next scheduled transmission time from the queue. Used by the simulation event scheduler.

Returns:: Next transmission start time in seconds
Return type:: float
Raises:: IndexError – If no assigned times remain

property goalTime: float | None

Get the goal time for this connection.

The goal time represents the total effective time that the connection will use the channel, calculated based on required and available capacity.

Returns:: Effective transmission time in seconds, or None if not calculated
Return type:: float or None

property id: int

Get the unique identifier of this connection.

Returns:: Connection ID
Return type:: int

insertTime(time: float) → None[source]

Insert a transmission time into the scheduled times queue.

Maintains the time queue in chronological order by inserting the new time at the appropriate position. Works with the simulation Future Event List (FEL).

Parameters:: time – Transmission start time in seconds to schedule

Note

Times are maintained in ascending order automatically.

nextSliceInAPWhenArriving(ap: AccessPoint) → int[source]

Determine the next available slice position when connection arrives.

Calculates which slice position will be active when this connection arrives, based on the arrival time and AP’s frame structure.

Parameters:: ap – Access Point to check
Returns:: Slice position (0 to ap.slicesInFrame - 1)
Return type:: int
Raises:: ValueError – If AP doesn’t have valid sliceTime or slicesInFrame

Note

Result is computed as: ceil(arrival_time / sliceTime) mod slicesInFrame

numberOfSlicesNeeded(capacityRequired: float, capacityFromAP: float) → int[source]

Calculate the number of TDM slices needed for this connection.

Determines how many time slices are required based on the capacity demand and the capacity provided by the access point.

Parameters:

capacityRequired – Required data capacity in bps
capacityFromAP – Available capacity from AP in bps

Returns:

Number of slices needed (rounded up)

Return type:

int

Raises:

ValueError – If capacityFromAP is zero or negative

Example:

slices = connection.numberOfSlicesNeeded(
    capacityRequired=1e6,  # 1 Mbps
    capacityFromAP=250e3   # 250 kbps per slice
)  # Returns 4 slices

property receiver: Receiver

Get the receiver associated with this connection.

Returns:: The receiver device for this connection
Return type:: Receiver

property snr: float

Get the Signal-to-Noise Ratio for this connection.

Returns:: SNR value (dimensionless), minimum value is sys.float_info.min
Return type:: float

property time: float

Get the arrival time of this connection.

Returns:: Time in seconds when this connection arrived in the simulation
Return type:: float