Scatternet and Piconets

Definition:
A scatternet is a network consisting of multiple interconnected piconets.

Piconet:
A piconet is a small network that consists of one master device and up to seven active slave devices. The master device controls the communication within the piconet.

Maximum Number of Piconets in a Scatternet:
The Bluetooth technology allows for the formation of a scatternet, which is a network of interconnected piconets. However, there are limitations on the maximum number of piconets that can be formed within a scatternet.

The correct answer to the given question is option 'A' - a scatternet can have a maximum of 10 piconets.

Explanation:
The Bluetooth technology uses frequency hopping spread spectrum (FHSS) to enable communication. In FHSS, the frequency band is divided into multiple channels, and devices hop between these channels at regular intervals.

In a scatternet, each piconet operates on a different frequency channel. The frequency hopping pattern is determined by the master device of each piconet. The master device controls the hopping sequence and informs the slave devices about it.

Reasoning:
To understand why a scatternet can have a maximum of 10 piconets, we need to consider the available frequency channels and the limitations of the Bluetooth technology.

Bluetooth operates in the 2.4 GHz frequency band, which is divided into 79 channels, each with a bandwidth of 1 MHz. However, only 23 channels are available for data transmission, while the remaining channels are used for other purposes like inquiry and paging.

In a piconet, the master device and the slave devices communicate using a single frequency channel. Therefore, the maximum number of piconets that can coexist without interference is limited by the number of available frequency channels.

Out of the 23 available channels, 3 channels are used for synchronization and control purposes, leaving 20 channels for data transmission. Each piconet requires at least one channel for communication, so the maximum number of piconets that can be formed is 20.

However, in a scatternet, the frequency hopping pattern of each piconet must be orthogonal to avoid interference. Orthogonal hopping patterns ensure that devices in different piconets do not transmit or receive data on the same channel at the same time.

To achieve orthogonality, the Bluetooth technology limits the number of piconets in a scatternet to 10. This allows for a sufficient number of orthogonal hopping patterns to be generated, ensuring minimal interference between piconets.

Conclusion:
In conclusion, a scatternet can have a maximum of 10 piconets. This limitation is due to the available frequency channels and the need for orthogonal hopping patterns to avoid interference between piconets.