An Enhanced Radio Resource Allocation Approach for Efficient MBMS Service Provision in UTRAN

Transcription

1 An Enhanced Radio Resource Allocation Approach for Efficient MBMS Service Provision in UTRAN Christophoros Christophorou, Andreas Pitsillides, Vasos Vassiliou Computer Science Department University of Cyprus Nicosia, Cyprus Abstract As currently specified by 3GPP, MBMS (Multimedia Broadcast Multicast Service) content can be provided in a cell by either Point-to-Point (P-t-P) or Point-to-Multipoint (P-t-M) transmission mode, but not both at the same time. In earlier work we highlighted the deficiencies of the current approach and proposed the concept of the Dual transmission mode cell, in which P-t-P (DCH) and P-t-M (FACH) transmissions can coexist and allowed to dynamically adapt through time, to address them. In this paper we further analyze the deficiencies of the current 3GPP approach and enhance our previous work to efficiently address the problem in high mobility scenarios as well. The proposed algorithm takes into consideration both the distribution and the movement of the MBMS users within the cell (using the CPICH Ec/No signal strength as a reference) and dynamically decides which MBMS users should be served using FACH and which should be served using DCH. Simulation results show significant transmission power savings, considerable reduction on the aggregated signaling and processing effort introduced, while QoS requirements are still fulfilled. Keywords-MBMS; UTRAN; MBMS content provision; Radio Resource Allocation I. INTRODUCTION Driven by the need for efficient data distribution when a large number of users want to receive the same data, the 3GPP consortium introduced in UMTS Release 6 specifications the MBMS (Multimedia Broadcast Multicast Service) system [1]. When using MBMS services, the main task of UTRAN (UMTS Terrestrial Radio Access Network) is to create and maintain an MBMS Radio Access Bearer (MBMS RAB) communication between the User Equipments (UEs) interested in the specific MBMS service (MBMS users) and the Core Network (CN), so that the MBMS QoS requirements are fulfilled in all respects. With this MBMS RAB (see Figure 1), the CN sends only one stream of data (through the MBMS Iu bearer) to the RNC (Radio Network Controller), irrespective of the number of Base Stations (BSs) or MBMS users that want to receive it. It is the RNC s job to replicate and distribute the MBMS content as efficiently as possible to the MBMS users in the cells. As currently specified by 3GPP in [2], MBMS content can be provided in a cell either by Point-to-Point (P-t-P) or Point-to-Multipoint (P-t-M) transmission mode, but not both at the same time (see Figure 1). If a P-t-P transmission mode is selected, one Dedicated Channel (DCH) is established for each MBMS user within the cell; otherwise, one Forward Access Channel (FACH) is established covering the whole cell s area and is commonly shared by all the MBMS users within. The decision of which transmission mode is going to be adopted is made by the RNC based on a radio resource efficiency criterion. In the initial 3GPP specifications [2], this criterion was based on a UE counting threshold; that is the number of MBMS users within a cell and belonging to the same multicast group that will justify a P-t-M transmission. Later, another approach [3][4] using the power required by each transmission mode (Power counting threshold) as the selection criterion was adopted. Based on [3][4], the RNC periodically and on a per cell basis, estimates the total amount of power required by each transmission mode and switches to the most efficient one. In [5] we highlighted the deficiencies of the current 3GPP specified MBMS service provision approach [2] and proposed a new scheme to address them by introducing the Dual transmission mode cell concept, in which P-t-P (DCH) and P-t-M (FACH) transmissions can coexist and dynamically adapt through time (by shrinking/expanding the FACH s coverage area and by establishing/releasing DCH connections), based on the instantaneous distribution of the MBMS users within it. This work is supported by the ICT C-CAST project.

2 Figure 1. MBMS RAB - Core and Radio Network use of resources, based on the current 3GPP specified MBMS service provision approach. In this paper we further analyze the deficiencies of the current 3GPP specified approach [2] and extent our previous work, to address efficiently high mobility (vehicular) scenarios as well. The enhanced algorithm, takes into consideration both the distribution and the movement of the MBMS users within the cell (both estimated using the CPICH Ec/No signal strength as a reference) and dynamically decides which MBMS users should receive the MBMS content using FACH and which of them should receive it using DCH. The aim is to achieve capacity, signaling and processing effort efficiency, while at the same time fulfill the QoS requirements in all respects. A similar idea, allowing the coexistence of DCHs and FACH within a cell, has been briefly mentioned in [6], but no detail has been provided for its implementation. The paper is organized as follows: In section II the need for a new MBMS service provision approach is motivated by emphasizing the deficiencies of the 3GPP approach, as currently specified in [2]. The proposed scheme is described in section III and evaluated in section IV. Finally, in section V we provide our conclusions and future work. II. NEED FOR A NEW MBMS SERVICE PROVISION APPROACH In order to motivate the need of a new MBMS service provision approach two scenarios are discussed, highlighting the deficiencies of the current 3GPP specified approach [2]. Cell s coverage limit Reduce power devoted to FACH to cover only the area where the MBMS users are located. (a) Current 3GPP specified approach - One FACH established covering the whole cell s area (results in capacity waste since all the MBMS users lies near the BS) (b) Optimal approach - FACH s coverage range is dynamically adapted to cover only the area where the MBMS users are distributed Figure 2. All MBMS users belonging to the same multicast group are distributed near the Base Station (at a radius closer than 600 meters from it) The first scenario (see Figure 2) considers the case where all the MBMS users belonging to the same multicast group are located near the BS, and the RNC justifies the use of a P-t-M transmission for the provision of the MBMS content in the cell. Based on the current 3GPP approach, a FACH covering the whole cell s area will be established (Figure 2.a) resulting in significant transmission power waste, since all the MBMS users are located near the BS and the actual downlink power required to be allocated for FACH in order to guarantee the MBMS service QoS at this distance is much less. Thus dynamic adaptation of FACH s coverage (Figure 2.b) is considered essential to avoid any excessive use of power. Establish one DCH for each MBMS user (except UE 1 & UE 2) and release FACH Establish one FACH and release all the DCHs (a) Current 3GPP specified approach Switch from P-t-M to P-t-P transmission mode and vice versa when the two UEs leave/re-join the MBMS session.

3 Release the two DCHs established for UE 1 and UE 2 Establish two DCHs (one for UE 1 and one for UE 2) (b) Optimal approach Allow the co-existence of P-t-M and P-t-P radio bearers. Figure 3. Two MBMS users (UE 1 and UE 2) located near the cell s edge are frequently leaving and re-joining the MBMS service The second scenario (see Figure 3) considers the case where a great number of MBMS users are located near the BS and two UEs (UE 1 & UE 2) located near the cell s edge are frequently leaving and re-joining the MBMS service causing a repetitive transmission mode switching between P-t-M and P-t-P (see Figure 3.a). Consider in this case the signaling traffic that will be introduced in the radio interface and the processing effort that will burden the RNC and the BS every time a transmission mode switching is justified (see Table I and II). This overhead can be avoided if instead of using only one transmission mode at a given time, we allow the coexistence of P-t-M and P-t-P transmissions (see Figure 3.b) and use one FACH for supporting the MBMS users near the BS and DCHs for UE 1 and UE 2. This solution can reduce the signaling and processing effort significantly, since every time UE 1 and UE 2 leave\re-join the MBMS session, only 2 DCHs will be released\re-established instead of for all the MBMS users. TABLE I. SIGNALING AND PROCESSING EFFORT INTRODUCED WHEN A FROM P-T-M TO P-T-P TRANSMISSION MODE SWITCHING IS JUSTIFIED (ESTABLISH ONE DCH FOR EACH MBMS USER AND RELEASE FACH) (1) RNC (*The following is performed for each MBMS user within the cell): Formats a Radio Link Addition Request message and sends it to the BS. (2) BS: On receipt of a Radio Link Addition Request message: Determines a spread code and channel ID for the new radio link. Creates a context record for the new UE. Sets up and configures the transmitter channel chosen for this link accordingly (Spreading Code, Data Rate etc). Formats a Radio Link Addition Response message and sends it to the RNC. (3) RNC: On Receipt of a Radio Link Addition Response message: Sets up the channel specified in the Radio Link Addition Response message received from the BS. Creates a buffer that will be used to queue the packets that will be transmitted on the associated channel. Creates the segmentation and reassembly buffers that will be used by the MAC. Creates the RLC profile record for the associated channel. Prepares the Physical Channel Reconfiguration message (size of 360 bits) with the necessary information and sends it to the associated UE. (4) UE: On Receipt of a Physical Channel Reconfiguration message: Reconfigure its GMM, RLC and MAC layers to receive the MBMS content through the associated DCH. Prepares the Physical Channel Reconfiguration Complete message (size of 56 bits) and sends it to the RNC. (5) RNC: On Receipt of a Physical Channel Reconfiguration Complete message: Configures and activates the associated transmitter channel at the BS in order to start transmitting the MBMS content to the UE. * The FACH is released after the Physical Channel Reconfiguration Complete messages are received from all the MBMS users. TABLE II. SIGNALING AND PROCESSING EFFORT INTRODUCED WHEN A FROM P-T-P TO P-T-M TRANSMISSION MODE SWITCHING IS JUSTIFIED (ESTABLISH ONE FACH AND RELEASE ALL DCHS) * Before releasing all the DCHs, the RNC sets up, configures and activates the FACH that will be used for the distribution of the MBMS Service content (1) RNC (*The following is performed for each MBMS user within the cell): Flushes and destroys the transmission, segmentation and reassembly buffers of the DCH to prevent the associated UE to receive packets on a channel that will be released. Prepares and sends a Physical Channel Reconfiguration message (size of 360 bits) with the necessary information to the associated UE. (2) UE: On Receipt of a Physical Channel Reconfiguration message: Release the DCH. Reconfigure its GMM, RLC and MAC layers to receive the content through

4 FACH. Prepares the Physical Channel Reconfiguration Complete message (size of 56 bits) and sends it to the RNC. (3) RNC: On Receipt of a Physical Channel Reconfiguration Complete message: Formats the Radio Link Delete Request message and sends it to the BS. (4) BS: On receipt of a Radio Link Delete Request message: Deletes the radio link by freeing the channel and spread code that are assigned for the UE specified in the Radio Link Delete Request message. Creates the Radio Link Delete Response message and sends it back to RNC. (5) RNC: On receipt of a Radio Link Delete Response message: Updates the RNC context record concerning the associated UE Releases the physical channel at the cell Destroys the RLC record of the released channel. The deficiencies of the current 3GPP specified approach discussed above and the solutions proposed, motivate the need for a new MBMS service provision approach in UTRAN. The proposed approach is described in section III. III. PROPOSED MBMS SERVICE PROVISION APPROACH The key point in the efficient MBMS service provision lies in the introduction of the Dual transmission mode cell in which P-t-M and P-t-P connections can coexist (see Figure 3.b) and allowed to dynamically adapt through time. The algorithm described here builds on previous work [5] and is enhanced in order to address efficiently high mobility (vehicular) scenarios as well. The algorithm, by taking into consideration the instantaneous MBMS users distribution and movement within the cell, dynamically estimates all possible transmission arrangements (i.e. estimates different combinations of which group of users should be served using FACH and which should be served using DCH) and selects the one that will reduce the total downlink power (capacity) consumption to the minimum required (referred as the optimum transmission arrangement ), while at the same time fulfill the QoS requirements in all respects. For easy reference, the algorithm is also summarized in Figure 4. The proposed algorithm consists of two phases; the Initialization phase and the MBMS Session Ongoing phase. Initialization phase: In order to identify the optimum transmission arrangement that will be adopted in a cell at the initialization of the MBMS session, the algorithm needs to create an initial image of how the MBMS users are distributed and moving in the cell. Thus, the RNC, just before the MBMS session starts, notifies all the MBMS users within the cell to report to it the instantaneous CPICH Ec/No signal strength and the CPICH Ec/No alteration rate (how fast the measured CPICH Ec/No signal strength is increasing or decreasing) experienced during their mobility. For each report received, one record is created for the related MBMS user in the Cell Context Information Table (CCIT) (see Table III) and placed in an ascending order based on the instantaneous CPICH Ec/No received signal strength value. The CCIT consists of five columns: UE s IMSI: International Mobile Subscriber Identity uniquely identifying the MBMS users. Instantaneous CPICH Ec/No received signal strength (measured in db): Depicts MBMS users distribution within the cell. It is worth clarifying that the criterion indicating how the MBMS users are distributed in the cell is not their distance from the BS but the CPICH Ec/No signal strength they received (i.e. channel quality based distribution). CPICH Ec/No Alteration Rate (db/sec): Indicates for each MBMS user within the cell, how fast the channel quality degrades (moving away from BS) or improves (moving towards BS) during its mobility. Power needed for DCH (watts): Estimated using eq. (1) described in [5]. Type of Connection: Set to DCH or FACH based on the optimum transmission arrangement adopted. TABLE III. CELL CONTEXT INFORMATION TABLE (CCIT) UE IMSI Instantaneous CPICH Ec/No Received Signal Strength CPICH Ec/No Alteration Rate Power needed for DCH Type of Connectio n TABLE IV. FACH POWER REQUIRED FOR GUARANTEEING A RELIABLE RECEPTION OF A 64 KBPS STREAMING VIDEO AT DIFFERENT ZONES AREAS Zone CPICH Ec/No Received FACH Power Area Signal Strength Required Z1 35 db (up to ~100 m) watts Z2 23 db (up to ~200 m) watts Z3 17 db (up to ~300 m) watts Cell Divided in ten Zones (Z1 Z10)

5 Z4 12 db (up to ~400 m) watts Z5 8 db (up to ~500 m) watts Z6 5 db (up to ~600 m) watts Z7 1.5 db (up to ~700 m) watts Z8-0.5 db (up to ~800 m) watts Z9-2.5 db (up to ~900 m) watts Z db (up to ~1000 m) watts * The information included in this table will be pre-estimated by the Network Operator. Table IV, on the other hand, includes information concerning the power that should be devoted to FACH in order to guarantee a reliable reception at different distances (referred as different Zone Areas) from the BS. Once all the responses are received, the algorithm uses CCIT and Table IV as input to estimate all possible transmissions arrangements and adopts among them the optimum one. In this example the cell is divided in ten zones areas (Z1 Z10) and the coverage limit of each zone area is defined based on a minimum required CPICH Ec/No received signal strength value. Using this example as a reference, eleven possible transmission arrangements exists: First: All DCHs (Similar to the P-t-P mode) Second: FACH for MBMS users included in Z1 (i.e. their instantaneous CPICH Ec/No received signal strength 35 db) and predicted (based on their CPICH Ec/No alteration rate) to stay within this Zone Area for the next C seconds. DCH for the others. The value of C is estimated by the RNC and provided to the algorithm. It equals the time required by the RNC in order to reliably switch an MBMS user from the FACH supported area to the DCH supported area, without any service interruption. In order to clarify more the role of this predictor parameter let us suppose the case of an MBMS user with instantaneous CPICH Ec/No signal strength equal to 38 db (i.e. lie within Z1), a CPICH Ec/No alteration rate equal to -3 db/second (i.e. channel quality is decreasing during its mobility), and a value of C equal to 3 seconds. In this case the MBMS user is predicted to leave Z1 in 1 second (since the CPICH Ec/No signal strength predicted to be experience by the MBMS user in 1 second will be equal to 35 db, which is equal to the coverage limit of Z1; see Table IV). Since the total time required by the RNC in order to reliably perform the intra-cell handover (i.e. switch the MBMS user from the FACH to the DCH supported area) is 3 seconds, even if the intra-cell handover is triggered immediately, it is obvious that supporting this MBMS user using FACH will result in QoS degradation (for a total time of 2 seconds) during the switching. Thus, by using this predictor parameter we assist the algorithm to avoid triggering late, and thus avoid any QoS degradation. If the predictor is not utilized, similar inefficiencies as described in [7] can be expected to occur. Third: FACH for MBMS users included in Z2 (i.e. their instantaneous CPICH Ec/No received signal strength 23 db) and predicted to stay in this Zone Area for the next C seconds. DCH for the others. Eleventh: One FACH covering the whole cell (up to Z10). Similar to the P-t-M mode. MBMS Ongoing Phase: Due to changes that can occur within the cell through time, i.e. due to the MBMS users mobility, the MBMS users should periodically report to the RNC their instantaneous CPICH Ec/No signal strength received. The CPICH Ec/No alteration rate is not required to be reported here since the algorithm can estimate it by itself using the previously instantaneous CPICH Ec/No signal strength included in the CCIT and the latest received values. Upon receiving the new reports, the algorithm will update the CCIT accordingly and then, in combination with Table IV, will search if a more efficient transmission arrangement than the one currently used exists. If a better transmission arrangement exists, the algorithm takes the appropriate actions in order for the new transmission arrangement to take place. Other events that that can occur and influence the cell s state are when an MBMS user joins/leaves the MBMS session, enters/leaves the cell (Inter- cell handover) or moves between the FACH and DCH supported areas (Intra-cell handover). In this paper we assume that the CCIT is updated every time one of the aforementioned events occurs. // INITIALIZATION PHASE // Using CCIT and Table IV estimate the total amount of downlink transmission power // required for every possible transmission arrangement and select the most efficient one Minimum Power = Sum of Power needed if all DCHs established Selected Zone = Z0 (Z0 refers to the case where all DCH connections are established) For i = 1 to 10 do { Total Power = FACH Power Required to cover Zi + Sum of DCHs Power Required for UEs outside Zi + Sum of DCHs Power Required for UEs within Zi but predicted to leave Zi in C sec If (Total Power < Minimum Power) then {

6 Minimum Power = Total Power Selected Zone = Zi } } In CCIT for every user in Selected Zone and NOT predicted to leave it in C sec Type of Connection = FACH Otherwise Type of Connection = DCH Based on Table IV, establish a FACH to cover the Selected Zone and support the MBMS users that lie within it and their Type of connection == FACH. For each MBMS user with Type of Connection == DCH establish one DCH // MBMS SESSION ONGOING PHASE Periodically and until the End of the MBMS SESSION do the following { // Search if a more efficient transmission arrangement than the one currently used exists. // Estimate again the transmission power required by each possible transmission // arrangement and compare with the one currently used if (Sum of Power needed if all DCHs established < Minimum Power) then { Minimum Power = Sum of Power needed if all DCHs established New Selected Zone = Z0 } For i = 1 to 10 do { Total Power = FACH Power Required to cover Zi + Sum of DCHs Power Required for UEs outside Zi + Sum of DCHs Power Required for UEs within Zi but predicted to leave Zi in C sec if (Total Power < Minimum Power) then { Minimum Power = Total Power New Selected Zone = Zi } } // When the optimum transmission arrangement is selected (indicated by // the value defined for the New Selected Zone) make the appropriate actions. if (New Selected Zone == Selected Zone) then Do Nothing. If a user joined/left the MBMS session, or performed an intra- or inter- cell handover, this assumed that is handled by a separate algorithm. A thorough study of efficient algorithms handling these events is a subject of our future work. if (New Selected Zone > Selected Zone) then { 1. Based on Table IV increase FACH power to cover the New Selected Zone 2. Based on the updated CCIT, for each MBMS user included in the New Selected Zone and its Type of Connection == DCH and NOT predicted to leave the New Selected Zone in C sec: a. Send a Physical Channel Reconfiguration message with the necessary information in order to stop receiving the MBMS Service using DCH and start receiving it through FACH. b. Set its Type of Connection field equal to FACH. c. Release the DCH established for the associated MBMS user. 3. Set the Selected Zone equal to the New Selected Zone. } if (New Selected Zone < Selected Zone) then { 1. Based on the updated CCIT, for each MBMS user that lies outside of the New Selected Zone and its Type of Connection == FACH and also for each MBMS user that lies within the New Selected Zone but it is predicted to leave it in C sec. a. Establish a DCH. b. Send a Physical Channel Reconfiguration message with the necessary information in order to stop receiving the MBMS service through FACH and start receiving it using the associated DCH. c. Set its Type of Connection field equal to DCH. 2. Based on Table IV, decrease FACH s power to cover the New Selected Zone and support the MBMS users that lie within it and their Type of connection == FACH 3. Set the Selected Zone equal to the New Selected Zone} } Figure 4. Proposed algorithm description using pseudo-code IV. PERFORMANCE EVALUATION For the performance evaluation of the proposed scheme OPNET Modeller 11.0.A UMTS module [8] was used as a base for building the MBMS simulator [9]. For illustrating the feasibility, the gain and the usefulness of the proposed scheme the following scenario (see Figure 5) was used. Figure MBMS users randomly distributed and moving randomly with a vehicular speed (~50 Km/h) within the cell.

7 In the scenario depicted above, a total of 80 MBMS users randomly distributed within a cell (of 1000 meters radius coverage), are receiving a 64 Kbps MBMS streaming video with a BLER target value of 1%. All the users are set to move randomly within the cell with a vehicular speed selected using a uniform distribution between 40 and 50 Km/h. A vehicular environment is used and a log-normal shadow fading with 10 db standard deviation is assumed. A 20 ms TTI (Transmission Time Interval) and a convolutional channel coding with 1/3 coding rate is used. The downlink other-cell interference factor is Two instances of the same scenario have been simulated; using the approach currently specified by 3GPP [2] and our proposed approach respectively. The results collected relate to the capacity (power) requirements, the processing effort and signaling traffic introduced by each approach. From the results illustrated below, comparing the actual and average downlink power (capacity) used, and the processing effort and signaling traffic introduced by each approach, we observe that our approach achieved the following gains: Significant transmission power savings: By utilizing the dual transmission mode cell concept, the maximum total downlink power required is reduced from 2.38 to 1.46 watts (that is 39% decrease Figure 6), while the average downlink power used is reduced from to watts (that is 52% decrease Figure 7). Figure 6. Total downlink power required (watts) Proposed Approach Vs Current 3GPP Specified Approach Figure 7. Average downlink power used (watts) Proposed Approach Vs Current 3GPP Specified Approach Considerable reduction on the aggregated processing effort required in RNC and BS for the establishment or releasing of channels (see Table V): By allowing the co-existence and the ability of P-t-P and P-t-M transmissions to dynamically adapt through time, eliminated the sudden switching between P-t-P to P-t-M transmission modes (illustrated in Figure 3.a), and provided a smoother and more efficient transition between them. The total number of actions required for channel releasing is reduced from 243 to 10 (95.9% decrease) and for channel establishment is reduced from 323 to 12 (96.3% decrease). Although, with our proposed approach additional processing effort is introduced for the control of FACH s coverage range (shrink or expand), but this is considered negligible since only one command is sent by the RNC to the BS to reduce or increase the power devoted to FACH. TABLE V. AGGREGATED PROCESSING EFFORT INTRODUCED 3GPP Specified Proposed Approach Approach Action Times Times Action performed performed Establish 3 Establish FACH 1 FACH Release FACH 3 Release FACH 0 Establish DCH 320 Establish DCH 11 Release DCH 240 Release DCH 10 Increase FACH s power expand 6 coverage* Reduce FACH s power shrink coverage* 6

8 * Negligible processing effort introduced. Considerable reduction on the aggregated signaling traffic introduced in the radio interface (see Table VI): This gain came as an additional benefit of the processing effort efficiency achieved. The aggregated downlink traffic introduced is reduced from to bits while the aggregated uplink traffic is reduced from to 5656 bits (that is 84% decrease on both downlink and uplink signaling traffic). TABLE VI. AGGREGATED SIGNALING TRAFFIC INTRODUCED 3GPP Specified Approach Proposed Approach Downlink bits Downlink bits Uplink bits Uplink 5656 bits V. CONCLUSIONS In this paper, we highlighted the deficiencies of the current 3GPP specified approach concerning the constrain set for not allowing P-t-P and P-t-M transmissions to coexist within a cell and adopt the Dual Transmission mode cell concept to address these deficiencies. We extend our previous work and enhance it, also addressing efficiently high mobility (vehicular) scenarios. The enhanced algorithm takes into consideration both the distribution and the movement of the MBMS users within the cell in order to decide the optimum transmission arrangement, aiming to achieve capacity, signaling and processing effort efficiency, while at the same time fulfill the QoS requirements in all respects. For the presented scenario (using vehicular speeds), we observed a 52% decrease on the average downlink power (capacity) used, a ~96% decrease on the aggregated processing effort required, and ~84% decrease on the aggregated signaling traffic introduced in the radio interface. A more detailed analysis of this algorithm including, the study of an efficient intra- and inter- cell handover algorithms and the use of HSDPA (High Speed Downlink Packet Access) for the MBMS service provision is a subject of our next research step. ACKNOWLEDGMENT The authors thank OPNET Technologies Inc. for providing the software license to carry out the simulations of this study. REFERENCES [1] 3GPP TS V8.0.0 ( ), Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional description (Release 8) [2] 3GPP TS V7.4.0 ( ), Introduction of the Multimedia Broadcast Multicast Service (MBMS) in the Radio Access Network (RAN); Stage 2 (Release 7). [3] 3GPP TR V7.1.0 ( ), Radio resource management strategies (Release 7), March [4] A. Panayides, C. Christophorou, J. Antoniou, A. Pitsillides, V. Vassiliou, Power Counting for Optimized Capacity in MBMS Enabled UTRAN, ISCC 2008, July 2008, Marrakech, Morocco. [5] C. Christophorou, A. Pitsillides, A new Approach for Efficient MBMS Service Provision in UTRAN, ISCC 2008, July 2008, Marrakech, Morocco. [6] M. Chuah, T. Hu, W. Luo, UMTS Release 99/4 airlink enhancement for supporting MBMS services, ICC 2004, Paris, France, June 2004, Vol: 6, Pages: [7] A.Pitsillides, C. Christophorou, MBMS Handover Control: A New Approach for Efficient Handover in MBMS Enabled 3G Cellular Networks, Elsevier Computer Networks Journal (COMNET), December 2007, ISSN: , Vol. 51, Issue: 18, Pages [8] OPNET University Program: university/ [9] B-BONE MBMS System Level simulator: