A. Sampath, N. B. Mandayam and J. M. Holtzman, \Erlang capacity of a power controlled integrated voice and data CDMA system", in Proc. IEEE VTC'97, NY, USA, 1997, vol. 3, pp. 1557-1561.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....high connection blocking probability. Erlang capacity is de ned as the average trac load in terms of the average number of users requesting services resulting in a prede ned connection blocking probability. Erlang capacity for a cellular CDMA system is studied in [31] for voice only trac, in [32] for integrated voice and data trac, and in [33] for heterogeneous trac. The Erlang capacity for given blocking probability is approximately analyzed in [31] taking into consideration of imperfect power control, activity factors, and di erent QoS requirements. A system supporting multiple trac ....

A. Sampath, N. B. Mandayam and J. M. Holtzman, \Erlang capacity of a power controlled integrated voice and data CDMA system", in Proc. IEEE VTC'97, NY, USA, 1997, vol. 3, pp. 1557-1561.

....v , while each data user aims for an E b =I 0 of fl d . 4. Since all the users will use the same bandwidth, then one server network will be adequate to represent one cell. Based on the above assumptions, the outage probability will be a function of the number of voice and data users in the cell [10]. Therefore, P (Z 1 Gamma j) P ( fl v G v nv X i=1 i fl d G d n d X i=1 i (1 Gamma j) where G v = W=R v is the processing gain for voice (W is the bandwidth, and R v is the voice rate) G d = W=R d is the processing gain for data,and j is a constant that represents the ....

A. Sampath and et. al. Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA Systems. IEEE 47th Vehicular Technology Conference Proceedings, pages 1557--561, May 1997

....in Watts. The received power in dB W is, by the above notation, given by S j = 10 log S j . ffl j is the signal to interference ratio (SIR or E b =I 0 ) for the j th user. 1 A rise over thermal noise admission policy [7] guarantees power control feasibility at the time of admission [8], and thus affects our probability of outage calculations. However, at all other times after admission, power control feasibility is not guaranteed, for this or any admission policy, and therefore needs to be considered during probability of outage calculations. Again, we see that our calculations ....

....in the admission policy suggested by Viterbi [7] users are admitted into the cell until the total interference seen at the base station exceeds the background noise level N 0 by a factor 1. It is shown Veeravalli Sendonaris: The Coverage Capacity Tradeoff in Cellular CDMA Systems 15 in [8] that this admission policy guarantees power control feasibility at the time of admission, which implies that the number of users admitted in the cell is smaller than k pole with high probability. However, to guarantee system stability at all times after admission, it would be necessary to always ....

A. Sampath, N. B. Mandayam, and J. M. Holtzman. Erlang capacity of a power controlled integrated voice and data CDMA system. In Proc. 1997 IEEE Veh. Technol. Conf., pages 1557--1561, Phoenix, AZ, May 1997.

....ratio variable X expressed in dB, X denotes 10 X=10 . ffl k denotes the number of users in the cell, i.e. those being controlled by the cell s base station (BS) 1 A rise over thermal noise admission policy [7] guarantees power control feasibility at the time of admission [8], and thus affects our probability of outage calculations. However, at all other times after admission, power control feasibility is not guaranteed, for this or any admission policy, and therefore needs to be considered during probability of outage calculations. We note that our calculations are ....

....can sometimes automatically be guaranteed by the admission policy. For example, in the admission policy suggested by Viterbi [7] users are admitted into the cell until the total interference seen at the base station exceeds the background noise level N 0 by a factor 1. It is shown in [8] that this admission policy guarantees power control feasibility at the time of admission, which implies that the number of users admitted in the cell is smaller than k pole with high probability. However, to guarantee system stability at all times after admission, it would be necessary to always ....

A. Sampath, N. B. Mandayam, and J. M. Holtzman. Erlang capacity of a power controlled integrated voice and data CDMA system. In Proc. 1997 IEEE Veh. Technol. Conf., pages 1557-- 1561, Phoenix, AZ, May 1997.

....in [2] and [6] is not suitable for www admission control. The mean value prediction scheme represents the case with no explicit access control and it is analyzed for comparison purposes. We design admission and packet scheduling based on the noise rise [1] condition, which was proved in [10] to satisfy the power control feasibility condition as well. In this paper we focus on the single cell case with perfect power control. Under more realistic assumptions (imperfect power control and multiple cells) the admission control imposes supplementary constraints [3, 17, 18] We also show ....

....(2) 3 3 Access Control for QoS Guarantees The role of the access control is to balance the system utilization such that QoS requirements are met for all users. We assume that SIR requirements for all calls in the system can be met if the total system load is maintained below some threshold [1] [10]. Denoting the system bandwidth as W, the noise rise condition can be expressed as: Z , Nv X i=1 SIR v i R v i Nw X i=1 SIR w i R w i # W (1 #) 3) where N v and Nw , represent the number of voice calls and www calls, R v i and R w i are the transmission rates for the i ....

A. Sampath, N.B. Mandayam, J.M. Holtzman. Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA System, IEEE Vehicular Technology Conference (VTC), 1997, vol 3, pp. 1557-1561.

....capacity left over after subtracting the voice contribution. Two di#erent schemes for predicting the future voice tra#c contribution to the system load are proposed and compared. Both admission and flow control are based on the noise rise [1] condition. If this condition holds, it was proved in [16] that the power control feasibility condition is satisfied as well. The paper is organized as follows: in section 2 we present the system and data models (voice and web tra#c) used in this work; section 3 describes the proposed access control with emphasis on the admission control in section 3.1, ....

....3 Access Control for QoS guarantees The role of the access control is to balance the system utilization such that QoS requirements are met for all users. We assume that SIR requirements for all calls in the system can be met if the total system load is maintained below some threshold [1] [16]. This represents the noise rise condition given as: Z , Nv X i=1 SIR v i R v i Nw X i=1 SIR w i R w i # W (1 #) 5) 4 where N v and Nw , represent the number of voice calls and www calls, R v i and R w i are the transmission rates for the i th voice and www ....

A. Sampath, N.B. Mandayam, J.M. Holtzman. Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA System, VTC'97, vol 3, pp 1557-1561. 21

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A. Sampath, N.B. Mandayam, J.M. Holtzman. Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA System, VTC'97, vol 3, pp 1557-1561.

....the residual capacity left over after subtracting the real time traffic contribution. Three different schemes for predicting the future voice traffic contribution to the system load are proposed and compared. Both admission and flow control algorithms are based on the noise rise condition [1] [2]. For the admission control, the condition should hold in an average sense, at a call arrival time scale. For the flow control, the condition should be valid on a slot by slot basis. If the noise rise condition holds, the Signal to Interference Ratios (SIRs) for all calls in the system can be ....

A. Sampath, N.B. Mandayam, J.M. Holtzman. Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA System, VTC'97, vol 3, pp 1557-1561.

....of the access protocol will follow the steps from section 3. To determine d(n) we impose a maximum value # for the conditioned outage probability: P out v,d (Z(n) 1 #) v(n) d(n) # #. 34) Conditioned on v(n) and d(n) Z(n) is a sum of lognormal random variables and it was shown in [9] that an accurate pdf model is a lognormal distribution. To simplify calculation, a gaussian approximation is used at this step (it was shown in [1] that the gaussian approximation yields more optimistic results compared with simulations but the di#erences remained within 1 error) Let A = G v G ....

A. Sampath, N.B. Mandayam, J.M. Holtzman. Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA System, VTC'97, vol 3, pp 1557-1561.

....for both voice and data. The design of the access protocol will follow the steps from section 3. To determine d(n) we impose a maximum value # for the outage probability conditioned on v(n) and d(n) Conditioned on v(n) and d(n) Z(n) is a sum of lognormal random variables and it was shown in [8] that an accurate pdf model is a lognormal distribution. To simplify calculation, a gaussian approximation is used at this step [1] Let A = G v G d (1 #) Then condition (20) can be rewritten as: Z # (n) G d v(n)# v i G v d(n)# d i A (21) The conditioned outage probability restriction ....

A. Sampath, N.B. Mandayam, and J.M. Holtzman, "Erlang capacity of a power controlled integrated voice and data CDMA system," VTC'97, vol 3, pp 1557-1561.

....situations of optimum power control as well as as retransmission schemes for data messages. While this work has considered the signal to interference ratio as a QoS measure to define Erlang capacity, an alternate definition is possible based on total interference power (as in [2] It is shown in [21] that the above outage condition is more stringent and hence ensures feasibility of the power control problem. An approximate analysis that takes into account imperfect power control, activity factors and different quality requirements is also presented. Another aspect of further investigation ....

A. Sampath, N. B. Mandayam, and J. Holtzman, "Erlang Capacity of a Power Controlled Integrated Voice and Data CDMA System", in Proceedings of IEEE VTC'97, May 1997, Phoenix, Arizona

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