GGE MS Protocol Stack (5)

XBM-WorkRoom

5. L1
General speaking, the development of Layer 1 shall involve in a number of essential elements, including a variety of hardware, for example MCU, DSP, RF and ABB, and drivers associated with hardware. In other words, the Layer-1’s development, some extent completely, depends on the platform selected. The following figure 7 shows the logical architecture of Layer 1 from the function.
                 Figure 7. Logical Functional Architecture of Physical Layer
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From the above diagram of the logical functional architecture of physical layer, it should be very obvious that the physical layer (namely layer 1) interfaces the Data Link Layer (Layer 2), the Radio Link Control and Medium Access Control Layer (RLC/MAC), and the Radio Resource management (RR) entity of layer 3. Furthermore, communication between the Physical Layer and the Data Link Layer or the RLC/MAC Layer or the RR entity of layer 3, is in an abstract way performed by means of PH-primitives and MPH-primitives through SAP between layers and layers, respectively. And the PH-primitives and the MPH-primitives individually indicate the different meanings in light of the corresponding context of layer, as specified by the following.
PH-primitives
To transfer the layer 2 frames and indicate the establishment of channel to layer 2
To transfer the RLC/MAC blocks and indicate the establishment of packet data physical channel (PDCH) to the RLC/MAC layer.
MPH-primitives
To assign the physical channel, measure the signals from serving or neighboring base station, etc.
In terms of a plenty variety of primitives, the Physical layer (Layer 1) shall provide the functions performed by the primitives for GSM and GPRS/EDGE separately, as follows.
GSM
Network synchronization &amp; Cell Selection (CS)
Full List receive level monitoring
Synchronization with a Neighbor Cell for CS
Camp on new serving cell for Cell Reselection
Failure from Network
Idle Mode
Full List receive level monitoring
Six strongest Neighbor cells BSIC and BCCH Reading
Serving Cell BCCH and PAGING reading
BA list Periodic Power Monitoring
Serving Cell CCCH and CBCH reading
Link Access
Dedicated mode
Dedicated Mode (such as Channel Assignment)
Six strongest Neighbor Cells, Synchro and Monitoring
BA list Periodic Power Monitoring
GPRS/EDGE
Packet Idle
Serving Cell Packet System Information (SI) Reading
Neighboring Cell Packet SI Reading
Serving Cell Packet Paging Reading
Serving Cell full PCCH reading
Cell Reselection Measurement
Packet Polling
Packet Access
Packet Transfer Mode (PTM)
Packet Transfer
Cell Selection Measurements In PTM
Interference Measurements In PTM
For these functions represented by kinds of primitives via the layer-to-layer SAP, what forms does the Physical Layer (Layer 1) should adopt in order to organize and represent them? Thinking … Alright, State Machine (SM)!  The SM shall solve the problem. So, The SM is able to help us effectively to deal with them relates to all functions from the Physical Layer. PLS hold on, however, I will introduce a new concept of SM, that is Finite State Machine (FSM) is one of all SMs, including FSM and IMS (Infinite State Machine).
What is the FSM? A Finite State Machine is device, or a model of a device, which has a finite number of states. It can be in at any given time and can operate on input to either make transitions from one state to another or to cause an output or action to take place. It should be noted that the FSM can only be in one state at any moment in time.
Ok, let’s come back to the main line.
The following Figure 8 is to represent the state transitions amongst these states of the Physical Layer.
            Figure 8. State Transitions in Finite State Machine of Physical Layer in MS
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In the Physical Layer of the MS the following states, which make up of the FSM of the overview of Layer 1, are defined:
NULL
The MS is switched off;
SEARCHING BCH
The Physical Layer tracks the best BCCH;
BCH
The Physical Layer listens to a BCCH/CCCH or PBCCH/PCCCH and is able to do random access;
TUNING DCH
The Physical Layer seizes on a respective dedicated physical channel or packet data physical channel;
DCH
The Physical Layer has seized a individual dedicated physical channel or packet data physical channel and may establish and through connect logical channels.

(PS: if you require and dicuss any further information of 3GPP and Protocol Stack, PLS visit the following website,
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