Wireless Oom » mac

How many instances of MAC for UE and Network?

wirelessoom — Sat, 31 Oct 2009 06:34:08 +0000

There is a single MAC instance within the UE.

In the network, usually a single MAC instance for each UE exists.
However, multiple MAC instances for a single UE may happen (e.g., one in a CRNC and one in an SRNC)

Layer 2 protocols

wirelessoom — Sat, 31 Oct 2009 06:28:01 +0000

Layer 2 protocols consists fo 4 protocol entities:

1. MAC (Medium access control)
2. RLC (Radio link control)
3. PDCP (Packet data convergence protocol)
4. BMC (Broadcast and multicast control)

What does MAC protocol do?

wirelessoom — Sun, 26 Jul 2009 13:31:21 +0000

The MAC is responsible for dynamic resource allocation under the control of RRC layer.

Using relative priorities betweeservices, MAC does

1. mapping between logical and the transport channels

2. transport format selection

3. priority handling of data flow

4. UE identification management to facilitate transactions such as random access and the use of downlink common channels

5. data ciphering when RLC is operating in transparent mode

6. traffic volume measurement (monitor the buffer levels for the different RLC instances)

Layer 2 consists of what protocol entities?

wirelessoom — Sun, 26 Jul 2009 13:22:39 +0000

Layer 2 comprises of 4 protocol entities.

1. MAC protocol

2. RLC protocol

3. PDCP (packet data convergence protocol)

4. BMC (broadcast and multicast control) protocol

Does MAC protocol segment MAC SDUs?

wirelessoom — Wed, 24 Jun 2009 14:01:47 +0000

No.

Is MAC layer delivery service guaranteed?

wirelessoom — Wed, 24 Jun 2009 13:59:58 +0000

No!

MAC layer transfer service is done in unacknowledged mode. That is, no guaranteed delivery service.

RLC layer has mechanisms to detect errors and retransmit.

Radio interface protocol structure

wirelessoom — Fri, 19 Jun 2009 04:09:55 +0000

Radio interface protocol structure:

Note that RB vs. SRB

At the UTRAN side, RLC and above protocols are located at RNC.

MAC protocols: some functionalities are at Node B, others are at RNC.