Performance Evaluation of Mobile Relays in CDMA System

1
Performance Evaluation of Mobile Relays in CDMA
System
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Supervisor
• Prof. Sven Gustav Häggman
• Instructor
• Prof. Riku Jäntti

• Presented By
• Md. Faisal Murad Hossain
• faisal_at_cc.hut.fi
• Communications Laboratory
• Helsinki University of Technology

2
Outline
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Introduction
• Wireless Network Overview
• (i) Cellular CDMA Network
• (ii) Infostation Network
• (iii) Multihop Cellular Network (MCN)
• Relaying Design Objective in MCN
• Mobility Model
• Basketball Multihop Scheduling
• Overview
• Pseudocode
• Relay Selection
• Performance Analysis
• Effect of User Density
• Effect of Cell Radius
• Conclusion

3
Introduction
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• The study of this thesis includes proposing a
  Scheduling Algorithm, for Mobile Relays in Uplink
  DS-CDMA, which we name as Basketball Multihop
  Scheduling Algorithm.
• We also compare its performance with other
  existing technologies e.g pure CDMA and
  Infostation Systems.

4
Wireless Network Overview(I)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Cellular CDMA Network
• The area that a base station covers around it, in
  which communication from and to the base station
  is achievable, is called its cell, thus the term
  comes cellular network
• It uses the multiplexing scheme CDMA, Code
  Division Multiple Access.
• Mobile stations communicate only with Base
  Stations.

5
Wireless Network Overview(II)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Infostation Network
• Any mobile node communicates with the base
  station only when they are close enough (within
  the transmit range).

6
Wireless Network Overview(III)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Multihop Cellular Network(MCN)
• In MCN the base station and mobile stations are
  not always reciprocally accessible in a single
  hop.
• The key advantage is that the mobile stations can
  directly communicate with each other provided
  that they are mutually reachable.
• MCN can perform multihop routing.

7
Relaying Design Objective in MCN
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Relaying Design Objective in MCN
• Communication range extension.
• Transmission through several hops.
• Higher data rates.
• Short hops-high data rate
• Better Quality.
• Cooperative Relaying
• original signal is received by several relays and
  forwarded to the destination through different
  paths so that it does not get stuck with a bad
  path and can be switched to a good path.
• Improved Capacity Again.
• simultaneous transmissions by both the BS and the
  relays.

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Mobility Model
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Mobility Model
• We used Directional Random Walk Mobility model.
• In the beginning of the simulation, each mobile
  node picks a random destination and traverses to
  that destination in a straight line at a uniform
  speed.
• When the destination is reached, each mobile node
  chooses a new destination
• Each mobile node has a higher probability in
  moving in the same direction as the previous
  move. And we assigned different probabilities for
  all other directions as shown in the figure,
• so that
• The new location of the mobile node depends
• on the previous location/direction and speed
• of the mobile node. When a mobile node
• reaches the boundary of the cell, it should
• flip-over to the reverse direction of the cell.

9
Basketball Multihop Scheduling(I)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Overview
• Basic idea is to deploy Multihop transmission
  from mobile nodes back to the base station.
• We utilize the similarity between the basketball
  game and our Multihop uplink packet scheduling
  problem. By regarding players, the basket and the
  ball as mobiles, the base station and data
  packet, respectively, we can mimic passing
  (Multihopping) patterns of the basketball
  players.
• A major difference between the two is that in the
  Multihopping problem, there are many packets
  (balls) while in the basket ball game, there is
  only one ball to shoot into the basket.
• For each CDMA time slot, a number of mobile nodes
  are selected as relays to let other nodes nearby
  to send the packets to them.
• A transmitting terminal may select a relaying
  node that is close to it and meanwhile the
  relaying node is located closer to the base
  station than that transmitting one.

10
Basketball Multihop Scheduling(II)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Overview (Contd.)
• There are two control parameters Transmission
  range r, and relay probability p.
• Scheduling rule
• A mobile will act as a relay with probability p.
• If it switch to relay mode, it only receives
  packet during the time slot.
• A mobile who does not act as relay will try to
  transmit
• If the base station is in its transmission range
  r, it will transmit to it directly.
• If base station is not in its range, the mobile
  will select the relay node which is closest to
  the base station and transmit the packet to it.
• If there are no relay nodes closer to the base
  station than the mobile itself, the mobile will
  remain idle during the slot.

11
Basketball Multihop Scheduling(III)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain
Node that tries to transmit
Relay node
Communication link
Base station
r
12
Basketball Multihop Scheduling(IV)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain
Is base station within radio range
Yes
No

• Transmit mode

Is there any relays within radio range
No
Yes
Is any relay closer to The base station than the
mobile itself
Yes
No
Transmit to the best relay within radio range
Stay idle
Transmit directly to the base station
Best relay relay closest to the base station
13
Basketball Multihop Scheduling(V)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Pseudocode
• At each slot
• We determined packet arrivals for all users
• We Checked which mobiles are relays
• We went through transmit mode users and
  determined active links
• We also determined SINR at the receiver of active
  links.
• Then we determined the packet transmissions in
  active link
• We removed transmitted packets from the
  transmission buffer of the source nodes and added
  them to the end of the queue at the destination
  nodes
• If packet were transmitted to the base station,
  we recorded the packet delay.

14
Basketball Multihop Scheduling(VI)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Relay Selection
• Let dij(t) denote the distance between mobile i
  and mobile j at time t. Let index 0 denote the
  base station so that di0(t) is the distance
  between mobile i and the base station at time
  instant t. Clearly, d00(t)0 for all t.
• Let M1,2,,N denote the set of all mobiles and
  let N0,1,2,,N denote the set of nodes
  including the base station (i0).
• Let R(t)µN denote the set of relay nodes at time
  slot, t. We assumed that a node i becomes a
  relay at time t with probability pi(t) 0,
  p0(t)1. That is the base station is always
  willing to act as a relay for all the nodes. All
  other nodes are wireless relays except the base
  station which relays the packet to the core
  network (e.g. internet).
• Let A(t)µM denote the set of active nodes. I.e.
  the nodes that are not acting as relays

15
Basketball Multihop Scheduling (VII)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Relay Selection (Contd.)
• A node i2A(t) selects relay ki using the
  following rule
• where 0?1 is a weighting parameter and Fi(t)
  denotes the set of feasible relays from mobile
  i.
• The feasible set includes all the nodes that are
  within the radio range r from the mobile i and
  are closer to the base station than the node i.
  The parameter 0lt?1 denotes a margin. A relay
  node is only accepted if its distance to the base
  station is less than that for node i.

16
Basketball Multihop Scheduling (VIII)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Relay Selection (Contd.)

Node transmitting a packet
Feasible relays Must lie in the intersection of
the two circles
Feasible (candidate) relay
?di0
Unfeasible relay
dj0
di0
j
dij
i
r
17
Performance Analysis(I)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Performance Analysis
• Simulation results are analyzed for the
  comparison of Basketball Multihop system with
  CDMA and Infostation systems with the help of CDF
  plots.
• Analysis based on Packet Delays and Throughputs
  for different systems.

18
Performance Analysis(II)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Table 1 Simulation Parameters

Parameter Value
No. of Nodes 100
Relay Probability 0.2
Simulation Time 120 sec
Radius of Cell 5 Km
Attenuation Factor 4
MS Transmit power 0.1 W
Noise Power 1 pW
Slot Length 10 mS
Mean Inter-Arrival Time (80e-3)/3 sec
Std. of Inter-Arrival Time 5e-3
Transmission Range 250 m
Min. Mobile Speed 701000/3600 m/s
Max. Mobile Speed 1001000/3600 m/s
Packet Size 10 bytes
Bandwidth 1.25e6 Hz
19
Performance Analysis(III)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Effect of User Density

Table 2 Mean and Variance of data (N100)
Packet Delay Packet Delay Normalized Throughput Normalized Throughput
Cases Mean (sec.) Variance (sec.) Mean Variance System Packet Delay (sec.) System Throughput (pkts/sec)
Basketball Multihop 0.6e3 CI0.96 7.8e5 1.1 CI 0.92 9.0 1.0 111.5
Pure CDMA 1.3e3 CI0.96 3.6e6 6.9 CI 1.0 119.6 6.1 697.8
One hop Infostation 2.2e3 CI 1.0 8.0e6 1.0 CI 1.0 18.8 0.9 103.6

• From Table 2, it can be said that with 100 users
  in the cell, the Basketball Multihop system
  incurs less mean packet delay than CDMA and
  Infostation systems. System Packet Delay for
  Basketball Multihop system is almost
• similar as Infostation system but significantly
  less than CDMA system.
• Again from Table 2, Throughput for Basketball
  Multihop is almost similar as Infostation system
  but worse than CDMA system.

20
Performance Analysis(IV)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• It can be seen from Figure 1 that for Basketball
  Multihop case, 80 of the time the packets will
  be delivered within 2000 time-slots whereas for
  CDMA case, 80 of the time the packets will be
  delivered within around 3000 time-slots and for
  Infostation case, 80 of the time the packets
  will be delivered within 4400 time-slots.
• Hence Basketball Multihop system is clearly
  better than the other two systems as the Service
  probability is better in this system with less
  delay maintaining good Quality of Service (QoS).

Figure 1 Comparison of Packet Delays for
different systems, N100
21
Performance Analysis(V)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Our results indicate that for Basketball Multihop
  case 100 users can be supported with 90
  probability whereas for CDMA case 92 users can be
  supported with 90 probability and for
  Infostation case 98 users can be supported with
  90 probability.
• Hence Basketball Multihop system is better than
  the other two systems with respect to Throughput.

Figure 2 Comparison of Throughputs for different
systems, N100
22
Performance Analysis(VI)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Effect of User Density (Contd.)

Table 3 Mean and Variance of data (N750)
Packet Delay Packet Delay Normalized Throughput Normalized Throughput
Cases Mean (sec.) Variance (sec.) Mean Variance System Packet Delay (sec.) System Throughput (pkts/sec)
Basketball Multihop 2.5e3 CI 1.0 6.8e6 11.1 CI 1.0 81.3 29.0 8.3e3
Pure CDMA 2.1e3 CI 1.0 5.3e6 2.0 CI 1.0 39.8 2.8 1.5e3
One hop Infostation 1.8e3 CI 1.0 6.3e6 0.8 CI 1.0 12.9 0.7 654.2

• From Table 3, it can be seen that with 750 users
  in the cell, the Basketball Multihop system
  incurs more packet delay than CDMA and
  Infostation systems.
• Again from Table 3, Throughput for Basketball
  Multihop is greatly increased than the other two
  systems.

23
Performance Analysis(VII)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• The results indicate that for Basketball Multihop
  case, 80 of the time the packets will be
  delivered within 6400 time-slots with 0.8 service
  probability and 0.2 outage probability, whereas
  for CDMA case, 80 of the time the packets will
  be delivered within around 4400 time-slots and
  for Infostation case, 80 of the time the packets
  will be delivered within 3800 time-slots.
• Hence Basketball Multihop system is worse than
  other two systems with respect to packet delays.

Figure 3 Comparison of Packet Delays for
different systems, N750
24
Performance Analysis(VIII)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• The results suggest that for basketball Multihop
  case 750 users can be supported with 95
  probability whereas for CDMA case 750 users can
  be supported with 95 probability and for
  Infostation case 750 users can be supported with
  85 probability.
• Thus, it can be said that if the number of user
  is increased, the Throughput for Basketball
  Multihop system is increased significantly,
  becomes stable with good service probability but
  incurs much packet delay.

Figure 4 Comparison of Throughputs for different
systems, N750
25
Performance Analysis(IX)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Effect of Cell Radius

Table 4 Mean and Variance of data (R1 Km)
Packet Delay Packet Delay Normalized Throughput Normalized Throughput
Cases Mean (sec.) Variance (sec.) Mean Variance System Packet Delay (sec.) System throughput (pkts/sec)
Basketball Multihop 211.5 CI 0.96 1.0e5 31.5 CI 0.96 0.07 2.1 3.1e3
Pure CDMA 2.4 e3 CI 0.96 7.3e6 23.0 CI 1.0 119.2 33.9 2.3e3
One hop Infostation 2.6e3 CI 0.96 6.3e6 12.5 CI 0.96 167.8 14.9 1.2e3

• It can be seen from Table 4, that Basketball
  Multihop system can provide less packet delay and
  more throughput than CDMA and Infostation systems
  in a small cell with 1 km radius.

26
Performance Analysis(X)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• From the Figure 5, it can be seen that for
  Basketball Multihop case, 80 of the time the
  packets will be delivered within 4000 time-slots
  with 0.8 service probability and 0.2 outage
  probability, whereas for CDMA case, 80 of the
  time the packets will be delivered within around
  4200 time-slots and for Infostation case, 80 of
  the time the packets will be delivered within
  5100 time-slots.
• Basketball Multihop system is better than the
  other two systems with respect to packet delays.

Figure 5 Comparison of Packet Delays for
different systems, R 1Km
27
Performance Analysis(XI)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• The results indicate that for basketball Multihop
  case 100 users can be supported with 100
  probability whereas for CDMA case 100 users can
  be supported with 96 probability and for
  Infostation case 100 users can be supported with
  96 probability.
• Basketball Multihop system is again better than
  other two systems with respect to Throughput.

Figure 6 Comparison of Throughputs for different
systems, R 1Km
28
Performance Analysis(XII)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Effect of Cell Radius (Contd.)

Table 5 Mean and Variance of data (R5 Km)
Packet Delay Packet Delay Normalized Throughput Normalized Throughput
Cases Mean (sec.) Variance (sec.) Mean Variance System Packet Delay (sec.) System throughput (pkts/sec)
Basketball Multihop 0.7e3 CI 0.96 6.9e5 7.1 CI 0.92 11.0 0.8 711.5
Pure CDMA 1.1e3 CI 0.96 3.3e6 4.9 CI 1.0 117.6 4.1 497.8
One hop Infostation 2.2e3 CI 1.0 8.0e6 1.0 CI 1.0 18.8 0.9 103.6

• From Table 5, it can be said that with large cell
  radius (5 Km) Basketball Multihop system provides
  less delay than the other two systems CDMA and
  Infostation systems.
• Again from Table 5, Throughput for Basketball
  Multihop is better than Infostation and CDMA
  systems when the cell radius is increased to 5Km.

29
Performance Analysis(XIII)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• The results suggest that for Basketball Multihop
  case, 80 of the time the packets will be
  delivered within 800 time-slots, whereas for CDMA
  case, 80 of the time the packets will be
  delivered within around 3000 time-slots and for
  Infostation case, 80 of the time the packets
  will be delivered within 3500 time-slots.
• Hence Basketball Multihop system is clearly
  better than the other two systems with respect to
  packet delays.

Figure 7 Comparison of Packet Delays for
different systems, R 5Km
30
Performance Analysis(XIV)
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• From the Figure 8, it can be seen that for
  Basketball Multihop case, from 28 to 100 users
  can be supported with 100 probability whereas
  for CDMA case from 32 to 100 users can be
  supported with 100 probability and for
  Infostation case from 28 to 100 users can be
  supported with 100 probability. Yet Basketball
  Multihop system is more stable than CDMA because
  it can provide any user with more than 80
  probability which CDMA cannot provide.
• Thus we can see that the Basketball Multihop
  system works better in a larger cell with respect
  to both Packet Delay and Throughput.

Figure 8 Comparison of Throughputs for different
systems, R 5Km
31
Conclusion
HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

• Conclusion
• The simulations have shown that there certainly
  is a need for relaying in cellular networks due
  to improved capacity and shorter delays.
• However the Basketball Multihop system works
  better for the following conditions
• More users for increased throughput and
  stability
• Larger cell for both shorter delay and improved
  throughput
• Highway-vehicle users for both increased
  throughput and improved delay
• High traffic volume for both shorter delays and
  higher throughput
• Short Transmission range for both improved delays
  and increased throughput.

32

HELSINKI UNIVERSITY OF TECHNOLOGY Performance
Evaluation of Mobile Relays in CDMA System Md.
Faisal Murad Hossain

Thank You Questions?