Sol12 - CHAPTER 12 Multiple Access Solutions to Review...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 CHAPTER 12 Multiple Access Solutions to Review Questions and Exercises Review Questions 1. The three categories of multiple access protocols discussed in this chapter are ran- dom access , controlled access , and channelization . 2. In random access methods, no station is superior to another station and none is assigned the control over another. Each station can transmit when it desires on the condition that it follows the predefined procedure. Three common protocols in this category are ALOHA , CSMA/CD , and CSMA/CA . 3. In controlled access methods , the stations consult one another to find which sta- tion has the right to send. A station cannot send unless it has been authorized by other stations. We discuss three popular controlled-access methods: reservation , polling , and token passing . 4. Channelization is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations. The common protocols in this category are FDMA , TDMA , and CDMA . 5. In random access methods, there is no access control (as there is in controlled access methods) and there is no predefined channels (as in channelization). Each station can transmit when it desires. This liberty may create collision . 6. In a random access method, there is no control; access is based on contention . In a controlled access method, either a central authority (in polling) or other stations (in reservation and token passing) control the access. Random access methods have less administration overhead. On the other hand, controlled access method are collision free. 7. In a random access method, the whole available bandwidth belongs to the station that wins the contention; the other stations needs to wait. In a channelization method, the available bandwidth is divided between the stations. If a station does not have data to send, the allocated channel remains idle. 8. In a controlled access method, the whole available bandwidth belongs to the sta- tion that is granted permission either by a central authority or by other stations. In a channelization method, the available bandwidth is divided between the stations. If a station does not have data to send the allocated channel remains idle.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 9. We do not need a multiple access method in this case. The local loop provides a dedicated point-to-point connection to the telephone office. 10.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Sol12 - CHAPTER 12 Multiple Access Solutions to Review...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online