ETSI TS 145 022 V13.0.0 (2016-01)

ETSI TS 1145 022 V13.0.0 (201616-01)

TECHNICAL SPECIFICATIONION
Digital cellular telecocommunications system (Phahase 2+);
Radio link managgement in hierarchical netwwoorks
(3GPP TS 45.0.022 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS
3GPP TS 45.022 version 13.0.0 Release 13 1 ETSI TS 145 022 V13.0.0 (2016-01)

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3GPP TS 45.022 version 13.0.0 Release 13 2 ETSI TS 145 022 V13.0.0 (2016-01)
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Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
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Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 6
1 Scope . 7
2 References . 7
3 Abbreviations . 7
4 General . 7
5 Hierarchical networks. 8
5.1 General . 8
5.2 Cell types . 8
5.2.1 Large cells . 8
5.2.2 Small cells . 8
5.2.3 Microcells . 8
6 Idle mode procedures . 9
7 Examples of handover and RF power control algorithms. . 9
7.1 General . 9
Annex A (informative): Example 1 (Siemens AG) . 10
A.1 Introduction . 10
A.2 Functional requirements . 10
A.3 BSS pre-processing and threshold comparisons. 11
A.3.1 Measurement averaging process . 11
A.3.2 Handover threshold comparison process . 11
A.4 BSS decision algorithm . 12
A.5 Additional O&M parameters stored for handover purposes in hierarchical networks . 12
A.6 Bibliography . 13
Annex B (informative): Example 2 (DeTeMobil) . 14
B.1 Introduction . 14
B.2 Definitions . 14
B.2.1 Categories of cells . 14
B.2.2 Classification of MS in connected mode . 15
B.2.2.1 Classification in the lower layer . 15
B.2.2.2 Classification in the middle layer or the upper layer . 15
B.2.2.3 Loss of the "slow MS" or "quasi-stationary MS" status . 16
B.3 Power Control Algorithm . 16
B.3.1 MS connected over a cell of the lower layer . 16
B.3.2 MS connected over a cell of the middle layer or the upper layer . 16
B.4 Handover algorithm in a hierarchical cell structure . 16
B.4.1 MS connected over a cell of the lower layer . 16
B.4.2 MS connected over a cell of the middle layer or the upper layer . 17
B.4.3 Handover at borders of different cell structures . 17
B.5 O&M-Parameter . 17
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B.6 State diagrams . 18
Annex C (informative): Example 3 (Alcatel) . 21
C.1 General description. 21
C.1.1 Speed discrimination . 21
C.2 Handover causes . 22
C.2.1 Emergency causes . 22
C.2.2 Better cell causes . 22
C.3 Dwell time in lower layer cells: . 22
C.3.1 Serving cell = lower layer cell . 22
C.3.2 Serving cell = upper layer cell . 22
C.3.3 Mechanism of increasing / decreasing tdwell . 22
C.4 Speed discrimination process: . 23
C.4.1 Serving cell = upperlayer cell . 23
C.4.2 Serving cell = lower layer cell . 23
C.5 Representation of handovers . 24
C.5.1 Ideal behaviour: target cells are available . 24
C.5.2 Real behaviour: target cells may not be available . 24
C.6 Emergency handover . 25
C.6.1 Target cell = upper layer cell . 25
C.7 Upper layer to lower layer cells handover . 26
C.7.1 General principles. 26
C.7.2 Homogeneity of speed discrimination in lower layer and upper layer cells . 26
C.8 Minicells . 26
C.8.1 Handover diagrams. 26
C.9 O&M parameters . 27
Annex D (informative): Example 4 (France Telecom/CNET) . 28
D.1 Introduction . 28
D.2 Descriptions of the algorithm . 29
D.3 Handover causes . 29
D.3.1 emergency handover causes . 29
D.3.2 mobile speeds estimation causes . 29
D.4 Mobile speeds estimations. 30
D.4.1 Estimation of the field strength variations . 30
D.5 BSS decision algorithm . 31
D.6 O&M parameters . 31
D.7 Examples . 32
D.8 State diagrams . 35
D.8.1 Case of a three layers hierarchical network . 35
D.8.2 Case of a two layers hierarchical network . 36
Annex E (informative): Simulation Model for Handover Performance Evaluation in
Hierarchical Cell Structures . 38
E.1 Introduction . 38
E.2 Mobile Environment. 38
E.3 Radio Network Model . . 38
E.3.1 Scenario 1: Hot Spot. 38
E.3.2 Scenario 2: Line of Cells . 39
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E.3.3 Scenario 3: Manhattan Coverage . 39
E.4 Propagation Model . 39
E.4.1 Upper Layer Path Loss . 39
E.4.1.1 Macrocells. 39
E.4.1.2 Small cells . 40
E.4.2 Lower Layer Path Loss . 41
E.4.2.1 Line-of-sight Case . 41
E.4.2.2 Non Line-of-sight Case . 42
E.4.2.3 Shape of the level with the proposed path loss model . 42
E.4.3 Fading . 43
E.5 Motion Model . 43
E.6 Handover Algorithms . 44
E.7 Measurement Reporting . 44
E.8 Performance Criteria . 44
E.9 Open Issues . 44
Annex F (informative): Change history . 45
History . 46

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Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
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1 Scope
The present document gives examples for the Radio sub-system link control to be implemented in the Base Station
System (BSS) and Mobile Switching Centre (MSC) of the GSM and DCS 1 800 systems in case hierarchical cell
structures are employed.
Unless otherwise specified, references to GSM also include DCS 1 800, and multiband systems if operated by a single
operator.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a
GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TS 03.22 (ETS 300 930): "Functions related to Mobile Station (MS) in idle mode and group
receive mode".
[2] 3GPP TR 03.30 (ETR 364): "Radio network planning aspects".
[3] 3GPP TS 45.008: "Radio subsystem link control".
[4] 3GPP TR 01.04 (ETR 350): "Abbreviations and acronyms".
3 Abbreviations
Abbreviations used in the present document are listed in 3GPP TR 01.04 [4].
4 General
ETS 300 911 (GSM 05.08 [3]) specifies the radio sub system link control implemented in the Mobile Station (MS),
Base Station System (BSS) and Mobile Switching Centre (MSC) of the GSM and DCS 1 800 systems of the European
digital cellular telecommunications system (Phase 2).
The present document gives several examples of how the basic handover and RF power control algorithm as contained
in (informative) annex A to ETS 300 911 [3] can be enhanced to cope with the requirements on the radio subsystem link
control in hierarchical networks.
A hierarchical network is a network consisting of multiple layers of cells, allowing for an increased traffic capacity and
performance compared to a single layer network.
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The radio sub-system link control aspects that are addressed are as follows:
- Handover;
- RF Power control.
5 Hierarchical networks
5.1 General
In a hierarchical, or microcellular network, traffic is supported on multiple layers of cells. Typically, a network operator
could implement a layer consisting of microcells as a second layer in his existing network consisting of large or small
cells. The addition of this second layer would improve the capacity and coverage of his network.
In the present document the following naming convention is used for the different layers. For a network consisting of
three layers the layer using the biggest cells is the "upper layer", followed by the "middle layer", and then the "lower
layer" which has the smallest cells. For a network consisting of two layers, only "upper layer" and "lower layer" are
used.
The intention in a hierarchical network is to use the radio link control procedures to handle the majority of the traffic in
the lower layer, i.e. the smallest cells, as this will limit interference and therefore improve the frequency reuse.
However, a part of the traffic cannot always efficiently be handled in the lower layer. Examples are cases where the MS
is moving fast (relative to the cell range), or where the coverage is insufficient, or where a cell to make a handover to on
the same level may not be available fast enough (going around corners, entering/leaving buildings).
5.2 Cell types
GSM 03.30 [2] distinguishes between three kinds of cells: large cells, small cells and micro cells. The main difference
between these kinds lies in the cell range, the antenna installation site, and the propagation model applying:
5.2.1 Large cells
In large cells the base station antenna is installed above the maximum height of the surrounding roof tops; the path loss
is determined mainly by diffraction and scattering at roof tops in the vicinity of the mobile i.e. the main rays propagate
above the roof tops; the cell radius is minimally 1 km and normally exceeds 3 km. Hata's model and its extension up to
2 000 MHz (COST 231-Hata model) can be used to calculate the path loss in such cells (GSM 03.30 [2] annex B).
5.2.2 Small cells
For small cell coverage the antenna is sited above the median but below the maximum height of the surrounding roof
tops and so therefore the path loss is determined by the same mechanisms as stated in subclause 5.1.1. However large
and small cells differ in terms of maximum range and for small cells the maximum range is typically less than 1-3 km.
In the case of small cells with a radius of less than 1 km the Hata model cannot be used.
The COST 231-Walfish-Ikegami model (see GSM 03.30 [2] annex B) gives the best approximation to the path loss
experienced when small cells with a radius of less than 5 km are implemented in urban environments. It can therefore
be used to estimate the BTS ERP required in order to provide a particular cell radius (typically in the range 200 m -
3 km).
5.2.3 Microcells
COST 231 defines a microcell as being a cell in which the base station antenna is mounted generally below roof top
level. Wave propagation is determined by diffraction and scattering around buildings i.e. the main rays propagate in
street canyons. COST 231 proposes an experimental model for microcell propagation when a free line of sight exists in
a street canyon (see GSM 03.30 [2]).
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The propagation loss in microcells increases sharply as the receiver moves out of line of sight, for example, around a
street corner. This can be taken into account by adding 20 dB to the propagation loss per corner, up to two or three
corners (the propagation being more of a guided type in this case). Beyond, the complete COST231-Walfish-Ikegami
model as presented in annex B of GSM 03.30 [2] should be used.
Microcells have a radius in the region of 200 to 300 metres and therefore exhibit different usage patterns from large and
small cells.
6 Idle mode procedures
GSM 03.22 [1] outlines how idle mode operation shall be implemented. Further details are given in Technical
Specifications GSM 04.08 and GSM 05.08 [3].
A useful feature for hierarchical networks is that cell prioritization, for Phase 2 MS, can be achieved during cell
reselection by the use of the reselection parameters optionally broadcast on the BCCH. Cells are reselected on the basis
of a parameter called C2 and the C2 value for each cell is given a positive or negative offset
(CELL_RESELECT_OFFSET) to encourage or discourage MSs to reselect that cell. A full range of positive and
negative offsets is provided to allow the incorporation of this feature into already operational networks.
The parameters used to calculate C2 are as follows:
a) CELL_RESELECT_OFFSET;
b) PENALTY_TIME;
When the MS places the cell on the list of the strongest carriers as specified in GSM 05.08 [3], it starts a timer
which expires after the PENALTY_TIME. This timer will be reset when the cell is taken off the list. For the
duration of this timer, C2 is given a negative offset. This will tend to prevent fast moving MSs from selecting the
cell.
c) TEMPORARY_OFFSET;
This is the amount of the negative offset described in (ii) above. An infinite value can be applied, but a number
of finite values are also possible.
The permitted values of these parameters and the way in which they are combined to calculate C2 are defined in
GSM 05.08 [3].
7 Examples of handover and RF power control
algorithms.
7.1 General
In the following annexes four examples of handover and power control algorithms are presented. All of these are
considered sufficient to allow successful implementation in hierarchical or microcellular networks. None of these
solutions is mandatory.
The "Description of algorithm" of each annex, contains a text as provided by the authors of the algorithm. Any
discussion on the algorithms is contained in a separate clause, "Discussion of algorithm".
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Annex A (informative):
Example 1 (Siemens AG)
Description of algorithm
Source: Siemens AG
Date: 23.08.95
Subject: Fast Moving Mobiles
A.1 Introduction
This annex specifies an enhanced handover algorithm that may be implemented in GSM or DCS 1 800 hierarchical
networks. In accordance with clause 5 of this annex a hierarchical network is understood as a network utilizing large
cells for the upper layer for wide area coverage, and a lower layer structure of small or micro cells for capacity reasons.
For the sake of simplicity the algorithm is described for hierarchical networks consisting of two layers. Nevertheless the
algorithm can be extended to a hierarchy comprising several layers.
The algorithm is based upon the basic handover process, as described in GSM 05.08 [3], annex A. Only differences and
supplements to the standard algorithms are explicitly described.
The aim of this annex is to show, how in hierarchical networks useless handovers can be avoided by allocating the
mobiles, according to their speed, to the appropriate cell type. This goal is achieved by steering the fast mobile stations
to the upper layer structure (e.g. large cells), while ensuring that slow mobile subscribers are served by the lower layer
structure (e.g. small or micro cells). A mobile station is considered as fast, if its sojourn time in a cell is short compared
to a mean call holding time.
An important aspect of this advanced algorithm is, that there is no implication on the MS type. The procedures
described in this annex, work in the same manner for Phase 2 as well as Phase 1 MS types.
A more comprehensive description of the advanced algorithm along with some investigation results based on handover
emulations in typical mixed cell scenarios is given in "Mobile Speed Sensitive Handover in a Mixed Cell Environment"
(see Bibliography).
A.2 Functional requirements
The present algorithm is based on the following additional assumptions:
- the upper layer structure (e.g. large cells) provides a contiguous wide area coverage for all MS power classes to
be supported by the network;
- the lower layer structure (e.g. small or micro cells) is fully embedded in the coverage area of upper layer
structure (e.g. large cells);
- the algorithm is based on both a power budget and absolute level criterion. Therefore both criteria shall be
enabled simultaneously, giving a higher priority to the absolute level criterion.
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A.3 BSS pre-processing and threshold comparisons
A.3.1 Measurement averaging process
In a mixed cell environment one should take into account the different propagation conditions in large and small or micro
cells, and the requirement for speeding up the handover decision, when a handover out of a small cell is pending (especially,
with the street corner effect in micro cells), an excessive delay of the handover detection can cause a loss of the connection.
Regarding this, the following items are recommended:
a) apply different values for the averaging parameters in large and small or micro cells, respectively;
b) define separate averaging parameters applicable to RXLEV and RXLEV_NCELL(n), respectively;
c) the BSS shall evaluate the Power Budget PBGT(n) using the averaging process defined for RXLEV_NCELL(n).
A.3.2 Handover threshold comparison process
The Handover threshold comparison process is similar to the process described in GSM 05.08 [3], annex A, except for
section e) in A.3.2.2, which is modified as follows:
e) Comparison of PBGT(n) with the variable hysteresis margin HO_MARGIN_TIME(n). If the process is
employed, the action to be taken is as follows:
If PBGT(n) > HO_MARGIN_TIME(n) a handover, cause PBGT(n), might be required.
In a hierarchical network this comparison enables handover into the lower layer structure (e.g. small or micro cells) to
be performed for slow mobile stations, while fast-moving ones remain served by the upper layer structure (e.g. large
cells).
The variable hysteresis margin is defined by:
HO_MARGIN_TIME(n) = HO_MARGIN(n) + HO_STATIC_OFFSET(n) - HO_DYNAMIC_OFFSET(n) * H(T(n) -
DELAY_TIME(n)).
In addition to the HO_MARGIN(n) as defined in table A.1 of GSM 05.08 [3] except that the range has been extended to
(-24, 24 dB), the variable hysteresis margin comprises:
- a static offset, HO_STATIC_OFFSET(n);
- a dynamic offset, HO_DYNAMIC_OFFSET(n); and
- a delay time interval, DELAY_TIME(n).
The parameters are related to cells of the lower layer structure only.
T(n) is the time that has elapsed since the point at which the mobile station has entered the coverage area of cell n in the
lower layer structure.
The function H(x) is defined by:
0 for x < 0
⎧ ⎫
H(x) = , with x = T(n) - DELAY_ TIME(n).
⎨ ⎬
1 for x ≥ 0
⎩ ⎭
The simultaneous fulfilment of the following conditions indicates that the mobile station has entered the coverage area
of cell n in the lower layer structure:
Condition 1: RXLEV_NCELL(n) > RXLEV_MIN(n) + Max(0,Pa)
Condition 2: PBGT(n) > HO_MARGIN(n),
where Pa = MS_TXPWR_MAX(n) - P.
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If both conditions are true, a timer T(n) shall be started. If any of these conditions gets false, before the timer expiry, the
timer shall be stopped and reset.
NOTE 1: HO_MARGIN_TIME(n) = HO_MARGIN(n) + HO_STATIC_OFFSET(n) for those cells of the lower
layer structure, whose timer has not yet been started or is still running. A high value of
HO_STATIC_OFFSET effectively prevents a handover into the respective cell of the lower layer
structure during the run time of the timer for that cell.
NOTE 2: HO_MARGIN_TIME(n) =HO_MARGIN(n) + HO_STATIC_OFFSET(n)
- HO_DYNAMIC_OFFSET(n)
for those cells of the lower layer structure, whose timer has expired. This is the margin fixing the cell
borders and replacing the usual HO_MARGIN(n) within the standard handover of GSM 05.08 [3],
annex A.
On timer expiry the reduced HO_MARGIN_TIME(n) allows for a power budget handover into a cell of
the lower layer structure for a slow moving mobile which is expected to be still in the coverage area of
that cell.
On the contrary, a fast moving mobile is expected to have left the coverage area of an embedded cell of
the lower layer structure while the timer for that cell is still running and therefore Condition 1 or 2 (or
both) will be violated, thus preventing a handover request for a fast moving mobile into that cell of the
lower layer structure. Consequently, fast moving mobiles are kept on the upper layer structure.
NOTE 3: A fast moving mobile connected to a cell of the lower layer structure (e.g. a phase 1 mobile being not able
to run the reselection algorithm in idle mode or a mobile having changed its speed) is steered to the upper
layer structure by requesting for it a rescue handover based on the absolute level criterion.
NOTE 4: HO_MARGIN(n) defines the location of timer start. Choosing small or even negative values results in an
early timer start and thereby avoiding cell border displacement and interference problems. Setting
HO_MARGIN(n) to large negative values effectively cancels Condition 2, and consequently the timer
start is triggered only by Condition 1 such that the cell borders on the lower layer structure are
independent of the cell site positions with respect to the cell sites in the upper layer structure.
A.4 BSS decision algorithm
The BSS decision algorithm described in GSM 05.08 [3], annex A, may be employed after replacing HO_MARGIN(n)
by the corresponding HO_MARGIN_TIME(n) in equation (2) of annex A. In combination with suitable parameter
settings this results in the mobile speed sensitive handover functionality referenced above.
A.5 Additional O&M parameters stored for handover
purposes in hierarchical networks
HO_STATIC_OFFSET(n) A parameter used to apply a positive offset to HO_MARGIN(n) in order to prevent a
handover request into cell n of the lower layer structure.
Range: 0 - 127 dB
Step Size: 1 dB.
Admin. for:  HO_STATIC_OFFSET(n) for each neighbour cell of  the lower layer
structure (n = 1 - 32)
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HO_DYNAMIC_OFFSET(n) A parameter used to partially or fully compensate the HO_STATIC_OFFSET(n)
for cell n of the lower layer structure. This parameter gets active after the time interval
DELAY_TIME(n).
Range: 0 - 127 dB
Step Size: 1 dB.
Admin. for:  HO_DYNAMIC_OFFSET(n) for each neighbour cell of  the lower
layer structure (n = 1 - 32)
DELAY_TIME(n) Time interval used to delay the handover decision into cell n of the lower layer structure to
enable differentiation between fast and slow mobile stations in the handover decision process.
Range: 0 - 255 T
sacch
Step Size: 1 T
sacch
Admin. for:  DELAY_TIME(n) for each neighbour cell of the lower  layer structure (n
= 1 - 32)
NOTE: These parameters apply only for cells of the lower layer structure.
A.6 Bibliography
1) K. Ivanov, G. Spring, "Mobile Speed Sensitive Handover in a Mixed Cell Environment", in Proc.
IEEE 45th Veh. Technol. Conf., VTC 1995, pp. 892-896.
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Annex B (informative):
Example 2 (DeTeMobil)
Description of algorithm
Source: DeTeMobil
Date:  21.08.1995
Subject: High speed MS
B.1 Introduction
In order to provide significantly more traffic capacity in GSM networks, the average cell size has to become smaller.
The reduction in cell size, however, should neither limit the mobility of the MS nor the MS speed. On the one hand
problems will occur if the MS are so fast, that the time they stay in a small cell is too short for the radio link control
procedures to be carried out efficiently and effectively and on the other hand if it is necessary to handover a MS to
predetermined target cells very quickly if the received RF signal level of a radio connection is changing rapidly in a
radio environment of small cells.
To give good performance to all MS, the network has to be built up using cells of different sizes at one place, i.e. a
hierarchical cell structure. The network provides a multi-coverage. Dependent on the MS speed, the MS shall be
handled by a cell with a suitable size.
The procedures to achieve this for an MS in idle mode are described in GSM 03.22 [1].
The radio link control procedures in the concept of a hierarchical cell structure are independent of the connections to
MSC and BSC.
In the following the procedures to handle MS in connected mode for a hierarchical cell structure are given.
B.2 Definitions
B.2.1 Categories of cells
A hierarchical cell structure is built up from different layers of cells. The structure shall allow at least three layers: the
lower layer, the middle layer and the upper layer(see note). If only two layers are planned, the lower layer and middle
layer are used. It is emphasized that the relation to other cells determines the assignment to a layer in the hierarchical
cell structure. The absolute size of a cell is not a criterion.
NOTE 1: An example for the use of middle and upper layer is as follows:
- Middle layer: Layer with sufficient capacity to handle the traffic for fast moving MS.
- Upper layer: "Umbrella Cells" of the middle layer, here only handover traffic shall be supported,
when cells of the middle layer are not available.
The layer to which a cell in a hierarchical cell structure is assigned is set by the O&M-parameter CELL_LEVEL.
Cells that do not belong into a hierarchical structure (single layer) have the CELL_LEVEL "standard layer" that is the
default level if details concerning the CELL_LEVEL are missing.
The parameter CELL_LEVEL has a range from 0 to 15(see note) and is allocated for each radio cell. The coding is
given in clause B.5. In each radio cell the own level, and the levels for all neighbour cells, as in the BA(SACCH), are
known.
ETSI
3GPP TS 45.022 version 13.0.0 Release 13 15 ETSI TS 145 022 V13.0.0 (2016-01)
NOTE 2: Possible reasons to introduce new layers may be: pico cells, specific services supported only in one layer,
multiband systems etc.
B.2.2 Classification of MS in connected mode
For radio link control purposes in a hierarchical cell structure, an MS in connected mode is classified by a set of at least
eight] status-fields. The set is called MS_STATUS. With one of these fields: MS_SPEED, MS are distinguished

between "fast MS", "slow MS" and "quasi-stationary MS". All other fields of the set are for future use (see note)
NOTE: Possible details given in the fields that are for future use are: multiple band, GPRS, EFR etc.
MS_STATUS is used in decisions of the power control process.
At the establishment of an RR-connection MS_SPEED is set to the default value "fast MS", except for Phase 2 MS if
establishment is in cells of the lower layer in which the path loss criterion C2 is activated. Then MS_SPEED is set to
"slow MS".
The speed classification can be enabled/disabled by the flag EN_MS_SPEED.
If the flag EN_MS_SPEED is set to 0 (disabled) in a cell of the lower layer the classification is omitted, and the status
of the MS in this cell will not be changed. At the establishment of an RR-connection all MS are set to the MS_SPEED
default value "fast MS". During handover the MS shall keep the status of the previous cell.
In cells of the middle layer or the upper layer, all cells of the lower layer with the flag EN_MS_SPEED disabled, are
excluded from the classification procedure as described in subclause B.2.2.2.
B.2.2.1 Classification in the lower layer
For each RR-connection supported by a cell of the lower layer a counter C is started. The counter C has an initial
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