CEPT
STG(10)27
ECC
Electronic Communications Committee
STG #22
WGSE - SEAMCAT Technical Group
ECO, Copenhagen
18 May 2010
Date Issued: 03 May 2010
Source :
ECO
Subject:
WiMAX specification in SEAMCAT
Document: for discussion
Summary
Extensive discussion between ECO and SAMSUNG/INTEL WiMAXs expert has lead to the
drafting of this document.
UL power control still need further specifications.
Proposal
STG is invited to consider the following specifications and to give feedback.
Background
OFMDA LTE module has been implemented in SEAMCAT. WiMAX is now to be
implemented in SEAMCAT has planned.
OFDMA WiMAX Algorithm - draft
Below is a draft of the specification to the implementation of WiMAX in SEAMCAT.
General assumption:
It is assumed that FDD WiMAX will be implemented in SEAMCAT, as a first phase. Implementation of TDD will need
further documentation. It is the 802.16e.
A load of 100% is assumed.
1
GENERAL FLOW - SIMULATION PROCEDURE FOR WIMAX
A. Parameters setup - Configure system deployment layout and simulation parameters.
i.
Parameters for cell radius, RF configuration (TX power, antenna pattern, pathoss model, shadowing,
penetration loss, etc.) are set up. (new inputs)
ii.
Parameters for simulation (total number of snap-shots, number of MS per sector, number of active
MS which represents the number of MS scheduled at once with equal resource amount). It is
assumed that each sector has exact the same number of simultaneously active MS in each snap-shot
throughout the simulation. (re-use)
B. BS location - Place subscriber stations in the service area with the selected base station deployment
i.
Cell layout configures 19 cells of 2 tiers as the ideal type. Each cell is composed of 3 sectors. (re-use)
with wrap arround is already implemented
ii.
Frequency reuse of 1 .
C. MS distribution (re-use)
i.
A large amount of MSs is randomly placed (40 Ues in each sector) with uniform distribution over the
whole service area for every snap-shot.
ii.
The necessary parameters are calculated between all sectors and each MS such as path loss,
shadowing, penetration loss, and antenna gain. The best server (sector) for each MS is determined
according to the SINR derived from the calculated parameters. At this stage only intra-system
interference is considered.
iii.
If any sector has less than 5 (as an example in this contribution) associated MS, go back to Step i.
iv.
For each sector, randomly choose 5 MS as simultaneously active MS among its entire associated MS
for this event.
D. SINR calculation (new equations see Table 4 and Table 5)
i.
SINR for an MS is calculated considering interference from both intra-system/co-channel (i.e. same
system-adjacent cell) and inter-system (i.e. external interference).
ii.
BS and MS are assumed to transmit at its maximum power.
2

For DL it is assumed that the BS transmit at maximum power.

At the time of the drafting of the specification, a typical UL power control was not available for
802.16e. Therefore, for the first phase of the implementation, the LTE power control will be kept
to allow flexibility to the tool. Nevertheless, If the SEAMCAT user wants to use full power
transmission at the UE _as recommended by the WiMAX experts, he can select the min and max
of MS to the same value. The min and max value will be set by default to the same value when
WiMAX is selected until the WiMAX community provides specifications.

The WiMAX UL power control algorithm will be provided in the future by the WiMAX
community. use ECC PT1 document algorithm. Further discussion may be required, in order to
optimize the speed of the PC. Currently, with 150 repetition, it may cause a burden to the
simulation time.

If further power control of WiMAX uplink is considered optionally, IEEE 802.16m [2] open loop
power control could be considered as defined in section 6. (802.16m is the advanced version of
802.16e)
E. Modulation efficiency calculation
F. Results collection
LTE
Bit rate loss
WiMAX
Modulation efficiency (new)
Outage (i.e. Loss of users) (new)
Bit rate loss  need link level mapping
as a first stage the LTE curves will be used.
Table 1: Summary of the ouput results for LTE and WiMAX
G. Repeat Steps C to F until the number of snap-shots is reached.
2
2.1
INPUT PARAMETERS
Deployment parameters
Input
Description
Comment for
implementation
Cell layout
Macro 19 clover-leaf cells, 3
sectors per cell
re-use (omni will be
disabled) it could be
possible to also use omni in
WiMAX
Cell size
Radius: R = 1 000 m
Spectrum band
2.500 ~ 2.690 GHz
re-use
re-use
Allocated bandwidth
5 MHz
re-use
802.16 system load
100%
In LTE, full load is assumed
In LTE, it is the ratio of the
RBs at the BS and MS
Active users
5 per sector (nomadic), 1 per
sector (fixed) After discussion
with Xinrong, it is possible to reuse
the LTE inputs, i.e. It may not be
needed to have a an extra field
3
Power control
No power control in 802.16e at the
time of drafting. WiMAX UL power
control algorithm will be provided
in the future.
Set min and max value of
the existing LTE PC to the
same value.
Base station antenna
type
Directional
Frequency reuse
(802.16)
1 × 3 × 1,
UE locations
Uniformly distributed
re-use
UE antenna type
Omnidirectional
re-use
Minimum coupling loss
between collocated
base stations
50 dB – Note that this coupling loss
is larger than that given in Reports
ITU-R M.2030 and (ITU-R M.2116);
however it lies within the range of
improved coupling losses given in
Report ITU-R M.2045.
re-use – change default
value
re-use
Frequency re-use of 1
Table 2: Common simulation assumptions and parameters ([1])
4
2.2
WiMAX parameters
BS
Comment for
implementation
MS
Max TX power (dBm)
36
24 (fixed)
20 (nomadic)
re-use
Antenna gain (dBi)
18
8 (fixed)
3 (nomadic)
re-use
Antenna height (m)
30
4 (fixed)
1.5 (nomadic)
re-use
ACLR @ 5 MHz (dB)
53.5
37 (fixed)
33 (nomadic)
Spectrum mask is used.
ACLR can be extracted for
information (see note)
ACLR @ 10 MHz (dB)
66
51
Spectrum mask is used.
ACLR can be extracted for
information (see note)
ACS @ 5 MHz)(dB)
70
40
re-use
ACS @ 10 MHz (dB)
70
59
re-use
3
5
re-use
Noise figure (dB)
Table 3: 802.16 FDD parameters (Editor’s note: this table is originally extracted from TDD material ([1]), FDD value
need to be check – see WiMAX representative in CEPT  see ECC PT1(10)065 annex 08 -- Wimax Forum 100301)
Note: In SEAMCAT, the ACLR is only given as information since the spectrum mask is the input parameter. With the
ACLR conversion implemented in SEAMCAT, it is easy for the user to set a spectrum mask so that it fits the desired
ACLR.
3
SINR MODELLING
SINR is given by:
N 
 nC IC ,i nA I A, j


10
10
10
SINR  S  10 log 10  10
 10
 10 
 i 1

j 1


N  –174  10 log 10 ( BW in Hz )  NF
where S is the desired signal strength (dBm) at the receiver
nC:
number of co-channel interfering transmissions (i.e. number of interfering links)
IC,i:
co-channel interference received from the ith transmitter (dBm)
nA:
number of adjacent channel interfering transmissions
IA,j:
adjacent channel interference received from the jth transmitter (dBm) as reduced by the ACS
and ACLR
N:
NF:
thermal noise (dBm)
system noise figure (dB).
For co-channel coexistence studies, the adjacent channel interference term in the above equation is ignored.
5
3.1
Intra-system/Co-channel Interference in DL
Frequency reuse 1 × 3 × 1: co-channel interference from downlinks of other sectors of the same cell and downlinks of
other cells of the same system. (existing)
3.2
Intra-system/Co-channel Interference in UL
Frequency reuse 1 × 3 × 1: co-channel interference from uplinks of other sectors of the same cell and uplinks of other
cells of the same system. (existing)
3.3
Inter-system to WiMAX / external interference to WiMAX
Within the WiMAX community, the ACLR and ACS methodology is considered. If the inter-system interference comes
from adjacent channel, it is reduced by ACIR (ACIR=(1/(1/ACLR+1/ACS)) in linear scale). ACLR is the adjacent channel
leakage ratio defined as the ratio between the power of in-band channel and the power of adjacent channel. ACS is
adjacent channel selectivity defined as the ratio of the attenuation of the receiver filter in its own channel to the
attenuation of the receiver filter in the adjacent channel. ACIR is modelled as flat in receiver’s bandwidth of victim
systems, i.e. the same value of ACIR is used for all resource assigned to MS.
This approach is very similar to what was done in 3 GPP, in SEAMCAT, the ACLR and ACS is not consider. Instead the
unwanted and the blocking calculations are performed.
Table 4 and Table 5 summarises the comparison of the SINR calculation in SEAMCAT between LTE and WiMAX for DL
and UL respectively. This eases to identify the similarities for the implementation of mobile WiMAX in SEAMCAT.
6
Directio
n
WiMAX
LTE
Frequency reuse: 1x3x1
DL
For WiMAX DL interferer:
 The carrier frequency of the WiMAX system is used as specified by the SEAMCAT user (i.e. f1 in the illustration
below),
 the spectrum mask is defined over the whole (5MHz) system bandwidth (ACLR can be extracted from the preview
feature in SEAMCAT). It is the same whether it is 1x3x1 or 1x3x3 frequency re-use scheme.
 The Tx power of the BS is scaled to the number of served UEs (see below)
5 UEs are sharing the whole bandwidth 5 MHz.
BW = X MHz per sector
BW = XMHz per sector
7
Full load system is assumed (i.e. all available RBs will
be allocated to active UEs) Each UE is scheduled with
the same number N of RBs. Thus, the BS transmit
power per UE is fixed.
Max
BS
Let P
UE
of PBS , i.e. same equation whether it is 1x3x1 or 1x3x3.
UE
BS
P
denotes the max. transmit power of BS
M  N  K is the number of all available RBs in
each cell
UE
PBS
is the transmit power from BS to the active UE,
N
UE
PBS
 PBSMax
.
M
Calculate DL C/I for all active UEs in all cells.
Loop over all cells from j  1 to N cell (the number
of cells in the system area e.g. 57 for 19 sites with
tri-sector antennas)
Loop over all active UEs from
C/I 
UE
PBS
is the transmit power from BS to the active UE (i.e. active link). The frequency re-use does not impact the calculation
Max
where PBS
PBSMax

NUE
denotes the maximum transmit power of the BS (in dBm) and NUE is the number of active UE served by a BS.
Max
Note that PBS is specified as input parameter to SEAMCAT.
Calculate DL C/I for all active UEs in all cells.
Loop over all cells/sectors from j=1 to nc = Ncell x Nsector (where Ncell is the number of cells in the system area e.g. 19 and
Nsector is the number of sectors per cell e.g. 3) and loop over all active UEs per sectors from k=1 to NUE (in this example NUE
= 5)
N
 nC IC ,i nA I A ,m

SINR  S  10 log 10  10 10  10 10  1010 
 i1

j 1


k  1 to K
C ( j, k )
I ( j, k )
SINR  S  10 log 10 I 
where S = C(j,k) which is the desired received signal from the j-th BS to its served k-th UE
UE
C( j, k )  PBS
 effective_ pathloss( BS j ,UE j ,k )
C(j,k) is the same whether a frequency re-use of 1x3x1 or 1x3x3 is considered. It is defined as
UE
C( j, k )  PBS
 effective_ pathloss( BS j ,UE j ,k )
where
I ( j, k )  I inter ( j, k )  I ext ( j, k )  Nt
effective_ pathloss (Tx, Rx )  max  pathloss  GTx  GRx , MCL
The interference I is defined as
nC
I C ,i
nA
I A ,m
N
I  10 10  10 10  1010
i 1
m 1
which is equivalent to
I ( j, k )  I inter ( j, k )  I ext ( j, k )  Nt
I = I(j,k) which is the total interfering signal to the link from the j-th BS to its served k-th UE, where Iinter is the co-channel
interference i.e. interference from its own system (Ic) and Iext is the external source of interference (IA) and the thermal
8
Noise Nt.
I inter ( j, k ) 
N cell
P
l 1,l  j
UE
BS
nC
 effective _ pathloss ( BS l ,UE j ,k )
Note: the term inter-system interference in LTE has a
different meaning than in WiMAX. It is equivalent to
the co-channel interference term in WiMAX
I int er   I C ,i
i 1
which is equivalent to
N cell N sec tor
I int er  
q 1
I
l 1
C , q ,l
where
I C , q ,l  P
UE
BSq ,l
 max  pathloss  GTx  GRx , MCL 
UE
where PBS
is the transmit power from the BS transmitter (in dBm) of the q-th cell and l-th sector to the its serving UE,
q ,l
GTx is the antenna gain (in dBi) of the BS, GRx is the antenna gain (in dBi) of the UE and MCL is the minimum coupling loss as
specified by the SEAMCAT user. Note that the antenna pattern effect from the BS to the victim UE is included. This effect is
different for different victim BS –UE combination since the locations are different.
nc = Ncell x Nsector and is dependent on the frequency re-use scheme as defined below:
co-channel interference from downlinks of other sectors of the same cell and downlinks of all the sectors of other cells of
the same system. (See illustration above)
For a tri-sector case (i.e. total BSs = 57):
nc = 56.
in other words, the co-channel interference experienced by the active link victims of the sector x of cell y can be written as
int er
I sec
tor  x , cell  y 
I ext ( j, k ) 
N External_ cell
 iRSS
m 1
unwanted
( BS m ,UE j ,k )  iRSS blocking ( BS m ,UE j ,k )
N cell  y N sec to r

 I C , q ,l 
q  y l 1, l  x
N cell
N secto r
 I
q 1, q  y l 1
C , q ,l
here Ncell = 19 and Nsector =3.
OFDMA WiMAX DL as victim:
nA
I ext   I A,m
m 1
where
I A,m  iRSS unwanted Extm ,UE j ,k  iRSS blocking Extm ,UE j ,k 
nA is the number of interferers and is equivalent to the Nexternal_cell of LTE
9
iRSS unwanted ( BS m , UE j ,k )  iRSS unwanted (over the size of the UE resource blocks)
Where iRSS unwanted ( Extm , UE j ,k ) is the amount of interference from Extm into the active link k-th UE connected to its j-th BS
(similar to ACLR)
iRSS unwanted
N sec tor  NUE
where iRSSuwanted is the amount of interference over the whole victim system bandwidth (specified by the SEAMCAT user)
and NUE is the number of victim WiMAX users connected to a BS (in your example, NUE = 5). Nsector is dependent on the
frequency re-use scheme.
iRSS unwanted ( Extm , UE j , k ) 
For a 1x3x1, Nsector = 1
Note: when the Ext are the BSs from WiMAX or LTE, it is all the BSs (e.g. 57 in tri-sector case) of the whole interfering
networks.
(equation below expressed in linear scale)
where
iRSSunwanted = PBSUE interferers x emissionit x effective_pathloss(BSext->UEvictim)
if the interfering links are considered in the calculation. PBSUEinterferers is the interfering power from the interfering BS to its
serving UEinterferers, i.e. PBSUEinterferers = PBS/NUEinterferers .
or
iRSSunwanted = PBS x emissionit x effective_pathloss(BSext->UEvictim)
if the BS (only) is considered. PBS is full power in this case
and where emissionit is the interference power integrated in the victim bandwidth (i.e. spectrum emission mask).
iRSS blocking ( BS m , UE j ,k )  iRSS blocking (over system bandwidth) 
N
M
Where iRSS blocking ( Extm ,UE j ,k ) is the amount of interference resulting from the blocking effect (similar to ACS) from the Extm
into the victim k-th UE connected to its j-th BS
iRSS blocking ( Extm ,UE j ,k ) 
iRSS blocking
N sector  NUE
where iRSSblocking is the amount of interference at the victim frequency and NUE is the number of victim WiMAX users
connected to a BS. Nsector is dependent on the frequency re-use scheme.
For a 1x3x1, Nsector = 1
Nt  10^ ((174  10 log 10(bandwith of N  RBs )  NoiseFigureUE ) / 10)
BW 
System _ Bandwidth
N sector
where System_Bandwidth is specified by the SEAMCAT user where Nsector is dependent on the frequency re-use scheme.
10
For 1x3x1, Nsector = 1
BW = 5 MHz
N  –174  10 log 10 ( BW in Hz )  NF
Table 4: Comparison of the SINR calculation in SEAMCAT between LTE and WiMAX for DL
11
direction
UL
WiMAX
LTE
Frequency reuse: 1x3x1
The LTE UL MS transmit over a bandwidth defined by
the number of RBs and at a carrier frequency
calculated based on the the number of MS so that
blocks of subcarriers are made.
For WiMAX UL interferer:
 The carrier frequency of the WiMAX system is used as specified by the SEAMCAT user,

the spectrum mask over the whole (5MHz) system bandwidth is used (ACLR can be extracted from preview in
SEAMCAT) and is the same whether it is 1x3x1 or 1x3x3 frequency re-use scheme.
 The Tx power of the UE is the same as specified by the SEAMCAT user (subject to PC)
5 UEs are sharing the whole bandwidth 5 MHz.
12
Calculate
UL C/I for all active UEs in the cells.
C ( j , k )  Pt ( j , k )  effective _ pathloss (UE j ,k , BS
j)
where Pt is the transmit power of the UE in dBm as
input to SEAMCAT (subject to power contol)
Loop over all cells/sectors from j=1 to nc = Ncell x Nsector (where Ncell is the number of cells in the system area e.g. 19 and
Nsector is the number of sectors per cell e.g. 3) and loop over all active UEs per sectors from k=1 to NUE (in this example NUE
= 5)
N
 nC I C ,i n A I A,m

SINR  S  10 log 10  10 10  10 10  1010 
 i 1

m 1


SINR  S  10 log 10 I 
where S = C(j,k) which is the desired received signal from the k-th UE into the j-th BS. C(j,k) is the same whether a
frequency re-use of 1x3x1 or 1x3x3 is considered. It is defined as
C ( j , k )  Pt ( j , k )  effective _ pathloss (UE j ,k , BS j )
where Pt is the transmit power of the UE (in dBm) as specified by the SEAMCAT user (subject to power contol).
I ( j, k )  I inter ( j, k )  I ext ( j, k )  Nt
The interference I is defined as
nC
I C ,i
nA
I A ,m
N
I  10 10  10 10  1010
i 1
m 1
which is equivalent to
I ( j, k )  I inter ( j, k )  I ext ( j, k )  Nt
I = I(j,k) which is the total interfering signal to the link from the k-th UE to j-th BS, where Iinter is the co-channel
interference i.e. interference from its own system (Ic) and Iext is the interference resulting from an external source of
interference (IA) and the thermal Noise Nt.
I inter ( j , k ) 
nC
N cell
 P (l, k )  effective_ pathloss(UE
l 1,l  j
t
l ,k
I int er   I C ,i
, BS j )
i 1
which is equivalent to
where Iinter is the interference coming from UEs of
the same system but from adjacent cells (i.e. the
inter-system interference from other cells). Since a
fully orthogonal system is assumed, only UEs which
transmit in the same frequency subcarriers will
introduce interference to each other, hence only UEs
in other cells with the same k index are considered.
N cell N sec tor NUE
I int er  
q 1
 I
l 1
r 1
C , q ,l , r
I C ,q,l  Pt  max  pathloss  GTx  GRx , MCL
where Pt is the Tx power from the UE in dBm as input to SEAMCAT (subject to power contol).
nc is the number of UEs from the same system causing co-channel interference (nc = Ncell x Nsector x NUE) is dependent on the
frequency re-use scheme as defined below:
13
co-channel interference from uplinks of other sectors of the same cell and uplinks of other cells (and sectors) of the same
system.
I
int er
sec tor  x ,cell  y

N cell y N sec tor NUE
  I
q  y l 1,l  x r 1

C , q ,l , r
N cell 1 N sec tor NUE
  I
q 1, j  y
l 1
r 1
C , q ,l , r
where Ncell =19, Ncell=y = 1, Nsector =3 and NUE =5.
I ext ( j , k ) 
N External_ cell K
  iRSS
m 1
1
blocking
nA
I ext   I A,m
(UEm, v , BS j )  iRSS unwanted (UEm, v , BS j )
m 1
where
I ext ( j, k ) 
N External_ cell  K
 iRSS
m 1
blocking
( Extm , BS j ,k )  iRSS unwanted ( Extm , BS j ,k )
where na is the total number of external interferer. If the interferer is cellular, it is equivalent to na = K x NUE where K is the
number of UEs in the interfering cells and Nexternal_cell which is the number of interference cells (the number of sectors are
included)
Unwanted:
OFDMA WiMAX UL as victim:
Where iRSS unwanted ( Extm , BS j ,k ) is the amount of interference from Extm into the victim link j-th BS and its serving k-th UE.
iRSS unwanted ( Extm , BS j , k ) 
iRSS unwanted
Nsec tor  NUE
where iRSSuwanted is the amount of interference over the whole victim system bandwidth and NUE is the number of victim
WiMAX users connected to a BS. When calculating the adjacent channel interference, each victim UE only get its own
portion of adjacent channel interference. For example, if the total adjacent channel interference to the whole 5MHz
bandwidth is I_total, then each user only get 1/5 of I_total since each desire user only uses 1/5 of the subcarriers.
Nsector is dependent on the frequency re-use scheme (see below).
Note: When Extm is a UE from WiMAX or LTE, it is all the UEs of the whole interfering network.
(equation below expressed in dB scale)
iRSS unwanted  Pt  emission it  effective_ pathloss where emissionit is the interference power integrated in the victim
WiMAX system bandwidth.
14
For 1x3x1, Nsector = 1.
Blocking calculated at the interfering frequency
using the ACS value
where iRSS blocking ( Extm , BS j ,k ) is the blocking value calculated at the interfering frequency using the ACS value as specified
by the SEAMCAT user.
iRSS blocking ( Extm ,UE j ,k ) 
iRSS blocking
N sector  NUE
where iRSSblocking is the amount of interference at the victim frequency and NUE is the number of victim WiMAX users
connected to a BS. It is defined as
(equation below expressed in dB scale)
iRSS blocking  Pt  effective_ pathloss  ACS
The ACS UL is the value for the whole system, therefore since each of the interfered links in the UL direction are only a
fraction of the used bandwidth, therefore the equivalent ACS for one link should also be a fraction it.
Nsector is dependent on the frequency re-use scheme.
For 1x3x1, Nsector = 1.
Nt  10^ ((174  10 log 10(bandwith of N  RBs )  NoiseFigureUE ) / 10)
BW 
System _ Bandwidth
N sector  NUE
where System_Bandwidth is specified by the SEAMCAT user (i.e. in this example 5 MHz) where N UE is the number of victim
WiMAX users connected to a BS (in your example, it is 5). N sector is dependent on the frequency re-use scheme.
For 1x3x1, Nsector = 1.
N  –174  10 log 10 ( BW in Hz )  NF
Table 5: Comparison of the SINR calculation in SEAMCAT between LTE and WiMAX for UL
15
4
FREQUENCY REUSE SCHEME
Frequency reuse schemes of 1 × 3 × 1 and 1 × 3 × 3 in the WiMAX system are shown in Figure 3.
Figure 3. Frequency reuse schemes 1 × 3 × 1
Following is how frequency reuse schemes (1 × 3 × 1) and loading factor (100%) are defined. For frequency reuse 1 × 3
× 1, each sector in the whole service area uses the same 5 MHz (as an example) bandwidth. Each sector independently
and randomly chooses 100% sub-carriers within the whole 5 MHz bandwidth as this sector’s active sub-carriers. Each
sector has five (as an example) simultaneously active users. Each sector evenly and randomly divides its active subcarriers between users.
In the simulation model, no matter how much bandwidth a BS or a UE occupies, it always transmits at its maximum
power. In other words, the power is transmitted on those carriers that are used.
At any given instance there is only one active user per sector in the 802.16 (fixed). It occupies the whole bandwidth
and transmits at its maximum power. For 802.16 (nomadic), there are five active users per sector at any given time.
Each user occupies one fifth of the whole bandwidth and transmits at its maximum power. Users are uniformly
distributed in the service area. For example, in the 1×3×1 nomadic case, 100% of the base station power is distributed
over 100% of the carriers, and 100% of the UE power is distributed over 1/5 of the carriers.
5
MODULATION EFFICIENCY CALCULATION
In the simulations, after each simulation of a snap-shot SINR at each WiMAX receiver is collected.
In order to get WiMAX system level performance, WiMAX link level performance results have to be obtained. The
following table shows an example of the WiMAX link level performance simulation results in AWGN.
Editor’s note: In other words, there is a direct mapping of the SINR calculated and the SNR used to evaluate the
modulation efficiency. Meaning that _as an example_ if for one link a SINR of 5.2 dB is calculated then it is equal to a
SNR of 5.2 dB which gives a MEi = 1.5.
WiMAX physical layer is modeled. Neither ARQ nor scheduler gain (multi-user diversity) is included. The following
table gives the required SNR to achieve the corresponding coding and modulation schemes for 1% packet error rate
(PER) of 100 bytes convolutional turbo-coded (CTC) packets. Each result is averaged over 10,000 packets.
Outage is subsequently evaluated for WiMAX. Outage occurs when the link SINR drops below –5.88 dB. (Editor’s note:
In LTE, there was no outage of MS. This is new output results. STG will consider whether it is needed or not)
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Note that this table could be changed according to transmission environments such as channel type, downlink or
uplink transmission. This value is dependent on channel, system configuration, etc. Therefore, the SEAMCAT user will
be able to fill in the table.
SNR
Modulation efficiency
relative to 1/2 rate-coded
QPSK
QPSK CTC ½,6
–5.88
1/6
QPSK CTC ½,4
–4.12
1/4
QPSK CTC ½,2
–1.1
0.5
QPSK CTC ½
1.9
1
QPSK CTC ¾
5.2
1.5
16-QAM CTC ½
7.2
2
16-QAM CTC ¾
11.6
3
64-QAM CTC 2/3
15.6
4
64-QAM CTC ¾
17.3
4.5
Table 6: Signal to noise ratio and modulation efficiency of WiMAX
physical layer for 1% PER
The WiMAX average modulation efficiency is calculated based on each link’s SINR and the SNR values in the above
table, assuming that the interference is noise-like. It is given by:
N
ME 
 MEi
i 1
N
where:
MEi:
N:
modulation efficiency of the ith link
number of total links.
The loss in the modulation efficiency is calculated by:
ME_loss  1 
MEmulti
MEsingle
where:
MEsingle :
average modulation efficiency of the WiMAX system without inter-system interference
MEmulti :
average modulation efficiency of the WiMAX system when coexisting with an interfering
system.
Modulation efficiency of 5% or 10% could be used as the system performance protection criteria.
(Editor’s note: In order to get the bit rate loss, like in LTE, there is a need to have mapping either from SINR -> bitrate
or modulation efficiency  bitrate.)
Xinrong: We can provide spectral efficiency vs SNR curves in the future if needed. Actually spectral efficiency loss is
equivalent to modulation efficiency loss.
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6
UL POWER CONTROL – OPTIONAL
TO BE DISCUSSED FURTHER
WiMAX UL power control (extracted from ECC PT1(10)065 annex 08 -- Wimax Forum 100301)
Power control in a mobile WiMAX MS is a mandatory feature identified in the Mobile WiMAX specification [19] and is
detailed in the IEEE 802.16 [18].
Under normal operational conditions, the WiMAX MS determines its TX power by the following equation,
P(dBm) = L + C ⁄ N + NI + Offset_SSperSS + Offset_BSperSS
where,
P
L
is the TX power level (dBm) per a subcarrier for the current transmission, including MS TX antenna gain;
is the estimated average current UL propagation loss. It shall include MS TX antenna gain and path loss, but
exclude the BS Rx antenna gain;
C/N
(new input field - table) is the target C/N of the modulation/FEC rate for the current transmission. Note that
it includes the number of repetitions for the modulation/FEC rate;
NI
is the estimated average power level (dBm) of the noise and interference per a subcarrier at BS, not
including BS Rx antenna gain;
Offset_SSperSS
is the correction term for UE-specific power offset. It is controlled by UE. Its initial value is zero;
(to be hard coded to zero in SEAMCAT)
Offset_BSperSS
is the correction term for UE-specific power offset. It is controlled by BS with power control
messages.
In the simulation, target C/N including R is provided in Table 6. Initially, BS decides each MS’s suitable UL target C/N by
its reported DL CINR.
C/N_target = 10 × log10(max(SINRmin, γIoT×CINRDL-0.5)).
where,
SINRmin (new input field) is the minimum UL SINR target of the system in linear scale, decided by BS;
γIOT
(new input field) is the fairness and IoT control factor, which is between 0.1 and 0.4;
CINRDL is the MS’s DL CINR in linear scale, which is measured by MS and to be reported to BS.
Following is the UL power control procedure in the simulation.
Step 1: BS decides MS’s MCS level by using the calculated C/N_target and Table 13.1.
This operation is done only once per event for each UEs (equally called MSs)
This means that each MS has its own CINRDL value so that:
CINRDL_i = (PBSmax/NUE)x effective_pathloss(BS,UEi)
Note that for the UL case, the knowledge of the BS transmit power is then also necessary (New field).
The C/N_target can be calculated for each of the UEs so that for UEi the corresponding C/N_targeti is defined as:
C/N_targeti = 10 × log10(max(SINRmin, γIoT×CINRDL_i-0.5)).
Where i-th is the index of the UE.
(1)
(2)
The C/N_target = SNR of table 6.
Example: if for UE1 connected to Cell1-BS1, the C/N_target1 = 7.2 dB, then this means that UE1 will be associated with
a 16-QAM CTC ½ and a Modulation efficiency ME = 2
Step 2: MS starts with a certain power level by WiMAX power control equation.
PUEi = Txpower+GUEi= L + C⁄N_targeti + NI + Offset_SSperSS + Offset_BsperSS
(3)
Where:
 L = Pathloss(BS,UEi) + GUEi where GUEi is antenna gain at the UEi and Pathloss(BS,UEi) is the pathloss between
the BS and the connected UEi.
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



C⁄N_targeti is calculated from step 1.
NI is the estimated average power level (dBm) of the noise and interference per a subcarrier at BS
o When WiMAX is interferer:
NI = ?
o When WiMAX is victim:
NI = ?
Offset_SSperSS = 0 dB
Offset_BsperSS = 0 dB
Therefore equation (3) can be rewritten such as:
PUEi = Txpower+GUEi= Pathloss(BS,UEi) + GUEi + C⁄N_targeti + NI + Offset_SSperSS + Offset_BsperSS
(4)
The GUEi can be removed which simplifies the equation in:
PUEi = Txpower = Pathloss(BS,UEi) + C⁄N_targeti + NI + Offset_SSperSS + Offset_BsperSS
(5)
Note: In Step 2, PUEi is equivalent to Pmin.
Step 3: Each MS’s UL, the SINR at the BS is calculated, including interference from the other system.
N
 nC IC ,i nA I A ,m

BS
BS
10
10
10 

SINRUE

S

10
log
10

10

10

UEi
10  
i

m1
 i1

(6)
Step 4: If MS’s UL SINR is lower than its MCS required SINR and the MS still has enough power room, the MS will
increase its TX power by 0.5 dB by setting Offset_BSperSS value.
Question: how do you quantify the “enough power room” ? I am calling it here P max
If (SINRUEiBS < C/N_target && PUEi < Pmax){
Offset_BsperSS = Offset_BsperSS + 0.5;
PUEi = Txpower = Pathloss(BS,UEi) + C⁄N_targeti + NI + Offset_SSperSS + Offset_BsperSS
}
Step 5: If MS’s UL SINR is higher than or equals to its “MCS required SINR plus 0.5 dB” and the MS’s TX power is not
less than “minimum TX power plus 0.5 dB”, the MS will reduce its TX power by 0.5 dB by setting Offset_BSperSS value.
If (SINRUEiBS ≥ C/N_target + 0.5 && PUEi > Pmin+0.5){
Offset_BsperSS = Offset_BsperSS - 0.5;
PUEi = Txpower = Pathloss(BS,UEi) + C⁄N_targeti + NI + Offset_SSperSS + Offset_BsperSS
}
Step 6: Go to step 3. Repeat 150 steps in the simulations, and then collect statistics.
Calculate SINRUEiBS using the final PUEi
7
REFERENCES
[1] Report ITU-R M.2113-1, Report on sharing studies in the 2500-2690 MHz band between IMT2000 and fixed broadband wireless access systems including nomadic applications in the same
geographical area
[2] IEEE 802.16m document, IEEE 802.16m Evaluation Methodology Document (EMD)
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