Near-Optimal Voice-Data Integration over Medium and
High Capacity Wireless TDMA Channels.
 A new Medium Access Control for mobile wireless communications is presented.
 Explore the performance of the protocol when integrating voice and data traffic over two
wireless channels:
a) Medium capacity  Outdoor microcellurar environment.
b) High capacity
 Indoor microcellurar environment.
 Uplink channel
Mobiles to base station-MAC scheme is required in order to resolve the source terminals
contetion.
 Downlink channel
The Base Station is the sole transmitter using Time Division Multiple Access.
Data message arrivals:
 are assumed to occur according to a Poisson process.
 Vary in length according to a geometric distribution.
Frame
Voice Data
R
R
R
v
v
d
Information




Information

.
R




d
.
.
ER
.
R
r
.
r
v
.
v
d
.
d
n
1
.
Voice request mini-slots
.
R
.
.
.
v
.
.
.
ER
r
1
.
n
.
Data request mini-slots
.
Three types of intervals.
 Voice Request intervals.
 Data Request intervals.
 Information intervals.

Request intervals are subdivided into minislots wich accommodate exactly one request
packet.

ER slots.

A standard request bandwidth of 2-3% is usually sufficient for optimum system performance.
TWO NOVEL IDEAS
 Certain request slots can be shared by voice and data terminals.
 Dynamic low - load mechanism.
 Voice and data terminals with packets, and no reservetion, contend for channel resources
using a random access protocol.
 Upon succesfully transmitting a request packet the terminal waits until the end of the
corresponding request interval to learn of it's reservation slot (slots).
LOW-VOICE LOAD MECHANISM
 Frame voice occupancy defined as the ratio of:
(Voice reservations + voice requests)
total number of information slots in the frame
 This ratio is calculated by the B.S immediately after the end of the voice request slots.
 If ratio > 50% then 1 slot/frame for data.
 If ratio < 50% then 8 slots/frame for data.
- Average data message length =8 packets.
 This allocation policy is temporary and only the first allocated slot is guaranteed to the data
terminals in subsequent frames.
TRANSMISSION PROTOCOLS
Data terminals
 Two-cell stack blocked access collision resolution algorithm.
Voice Terminals
 Two-cell stack reservation random access algorithm.
 Pre-spliting.
Frame structure for the 1.8 Mbps channel.
1 Slot
49 Slots
R


v
1
2
a
n
d

.
.
4
.
.
9
.
.
R
d
1
2
3
4
5
6
6 request minislots
Frame structure for the 9.045 Mbps channel.
4 slots
83 slots
1 slot
83 slots
1 slot
84 slots
Rv and Rd

1

R

.
8
d
8
.
3
.
1
2
3
4
4 request minislots
4

R

.
1
d
1
.
2
.
6
6
.
5
6
7
.

0
.
Experimental System Parameters
Design Parameters
Medium
High
Capacity
Capaci
Channel
ty
Chann
el
Channel Rate (Mbps)
1.8
9.045
32
32
12
12
50
256
240
46.875
1
6
Speech Codec Rate
(Kbps)
Frame Duration (ms)
Slots per Frame
Slot duration (μs)
Request
frame
slots
per
Minislots per request
slot
6
4
Packet size (bytes)
53
(
header)
5
53 ( 5
header
)
Voice
delay
limit
(ms)
Mean
24
1.41
1.41
1.78
1.78
0.01
0.01
24
125
200
200
talkspurt
duration (s)
Mean
silence
duration (s)
Maximum
voice
dropping probability
Low
24
frame
voice
occupancy
limit
(slots)
Average delay limit
for data message
Transmission (ms)
RESULTS
1) VDl-MCC (Voice Data Integration in a Medium Capacity Channel)
 Conceptual comparison with IPRMA.
 Use of PRMA algorithm to resolve voice terminal contetion.
 The absence of request slots.
 Does not provide absolute priority to voice traffic over data traffic.
 The static nature of it's low load mechanism.
- k idle slots
-speech priority of M slots
- A data user is allowed to reserve up k-M-1 slots.
RRA protocol
Differences
1. RRA uses two request slots, the second of which is used for data requests.
2.RRA does not use ER slots.
3. In RRA, the BS allocates resources at the end of each channel frame and not at the end of the
request slot of the current channel frame.
4. In RRA the BS preempts data reservations to service voice requests.
5. ln RRA data terminals may acquire only one information slot per frame.
RESULT COMPARISON OF VDI-MCC and RRA
A) Results for voice traffic only
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5
.
3
4
0
7
 Immediate slot allocation
 ER slots.
8
RESULT COMPARISON OF VDI-MCC and RRA
B) Results for data traffic only
 Data access Delay (DaD) is defined as the time period from the instant a data terminal
generates a message, until it completes the transmission of the first packet of its message.
 Data message delay (DmD) is defined as the time period from the instant a data terminal
generates a message, until it completes the transmission of the last packet of its message .
Due to:
 The immediate allocation of recources.
 The use of ER slots.
 The possible allocation of more than 1 slot per frame to the data terminals in low voice load
situations.
RESULT COMPARISON OF VDI-MCC and RRA
800,00
Delay(ms)
600,00
400,00
RRA (DaD)
200,00
RRA(DmD)
VDI-MCC (DaD)
5,87
5,83
5,80
5,75
5,30
3,00
2,55
2,00
1,00
0,40
0,00
0,00
VDI-MCC (DmD)
λ(m essages/fram e)
Steady state mean data delays in the absence of voice traffic
COMPARISON OF RESULTS BETWEEN VDI-MCC and RRA
C) Results for Voice-Data Integrated Access.
300,00
Delay(ms)
250,00
200,00
150,00
100,00
RRA (DaD)
50,00
RRA (DmD)
1,3
95,3
1,1
92,0
0,9
88,7
0,7
85,3
0,5
82,0
0,3
78,7
0,1
75,3
0,00
λ (m essages/fram e)
Steady state mean data delays: N=80.
VDI-MCC (DaD)
VDI-MCC (DmD)
600,00
Delay (ms)
500,00
400,00
300,00
200,00
RRA (DaD)
100,00
RRA (DmD)
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0,00
λ (m essages/fram e)
VDI-MCC (DaD)
VDI-MCC (DmD)
Steady state mean data delays: N=90.
 For Vts=80 RRA achieves a channel throughput of 90.3% (λ=1)
 For Vts=90 RRA achieves a channel throughput of 87.9% (λ=0.3)
 For Vts=80 VDI-MCC achieves a channel throughput of 91.8% (λ=1.2)
 For Vts=90 VDI-MCC achieves a channel throughput of 91% (λ=0.6)
λ (messages/
Max. Voice Capacity for Pdrop<1%
frame)
VDI-MCC
0.1
100
0.2
99
0.5
99
0.7
99
0.8
98
1.0
98
1.2
98
1.3
98
First QoS comparison of VDI-MCC and RRA.
λ
Max. Voice Capacity for Pdrop<1% and DmD<200 ms
(messages/fr
ame)
VDI-MCC
Cap.
RRA
Chan.
Pdrop
Voice
packetaccess
DmD (ms)
Cap.
Chan. Throu.
Pdrop (%)
Voice packet access delay (ms)
DmD
Throu.
(%)
delay (ms)
0.1
100
0.909
0.973
23.14
180.6
95
0.886
0.623
26.69
197.4
0.2
98
0.912
0.761
19.62
196.7
92
0.877
0.361
22.99
191.3
0.3
96
0.909
0.526
15.93
183.1
91
0.886
0.280
21.84
194.6
0.4
94
0.910
0.417
14.22
194.7
89
0.885
0.187
20.49
189.4
0.5
92
0.909
0.282
11.94
177.9
88
0.892
0.153
20.04
199.4
0.6
91
0.918
0.236
11.22
199.2
86
0.891
0.102
19.28
193.3
0.7
89
0.917
0.176
10.05
187.3
85
0.899
0.084
19.03
198.7
0.8
87
0.915
0.105
8.64
165.4
83
0.898
0.063
18.69
192.2
0.9
86
0.922
0.082
8.36
186.1
82
0.905
0.048
18.48
198.4
1.0
85
0.928
0.077
7.98
192.4
81
0.912
0.042
18.38
199.5
1.1
83
0.926
0.049
7.29
182.2
79
0.911
0.039
18.28
190.4
1.2
81
0.927
0.032
6.81
175.3
78
0.918
0.036
18.24
197.3
1.3
80
0.933
0.031
6.71
195.6
76
0.916
0.032
18.14
188.3
Second QoS comparison of VDI-MCC and RRA.
(ms)
VDI-HCC
 permanent request bandwidth = 6 slots
 Use of ER slots
 High channel capacity.
Leads VDI - HCC to achieve a near-optimal multiplexing gain.
voice traffic
 maximum voice capacity - 556 terminals.
 voice multiplexing gain 556/256=2.17
 The optimal multiplexing gain is (1 .41+1 .78)/1 .41=2.26
 voice packet throughput 243.5 packets/frame or 97 .4%
Voice Packet Dropping Prob. (%)
1.200
1.000
0.800
0.600
0.400
0.200
0.000
515 517 519 521 523 525 527 529 531 533 535 537 539 541 543 545 547 549 551 553 555 556 557
N, Active Voice Terminals
Steady state voice Pdrop versus the number of active voice terminals.
Mean Voice Packet Delay (ms)
30.00
25.00
20.00
15.00
10.00
5.00
0.00
515 517 519 521 523 525 527 529 531 533 535 537 539 541 543 545 547 549 551 553 555 556 557
N, Active Voice Terminals
Steady state mean voice access delay versus the number of active voice terminals.
1,000
0,800
0,600
λ=0.4
0,400
λ=1
0,200
λ=2
553
551
547
543
539
535
531
527
523
519
0,000
515
Voice Packet Dropping
Probability (%)
1,200
λ=9
N, Active Voice Term inals
Pdrop for different data message arrival rates.
Delay(ms)
400,00
300,00
200,00
100,00
Data Packet Access Delay
2,600
99,4
2,200
98,1
1,800
96,8
1,400
95,5
1,000
94,3
0,600
93,0
0,200
91,7
0,00
Data Message Delay
λ(m essages/fram e), channel
throughput(%)
Steady state mean data delays with N=515 active voice terminals.
λ (messages/frame)
Max. Voice Capacity for Pdrop<1% and DmD<200
ms
VDI-HCC
Capacity
Channel
Pdrop (%)
DmD (ms)
Throughput
0.2
544
0.963
0.469
195.9
0.4
538
0.960
0.292
198.6
0.6
535
0.961
0.242
189.3
0.8
530
0.962
0.184
192.4
1.0
525
0.960
0.139
187.8
1.5
520
0.966
0.098
193.0
2.0
511
0.966
0.035
182.3
2.5
505
0.972
0.029
187.4
3.0
500
0.977
0.021
188.3
4.0
486
0.982
0.015
199.6
5.0
469
0.985
0.012
196.5
6.0
448
0.981
0.007
189.9
7.0
427
0.980
0.006
193.3
8.0
409
0.979
0.005
198.2
9.0
391
0.979
0.003
193.6
10.0
372
0.977
0.003
187.2
Performance of VDI-HCC when fulfilling both the QoS requirements.