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Showing papers on "Handover published in 1993"


Journal ArticleDOI
TL;DR: Analysis of a wireless network having a two-tier architecture to serve both conventional mobile subscribers and quasi-stationary subscribers shows that the capacity tradeoffs are poor for Systems I and II because of the large amounts of cross-tier interference: and that System IV gives the best capacity tradeoff.
Abstract: Th authors explore the use of a wireless network having a two-tier architecture to serve both conventional mobile subscribers and quasi-stationary (e.g., PCN (personal communications network)) subscribers. The latter are served by microcells which are embedded within macrocells that serve the mobile users. This provides a balance between maximizing the number of users per unit area (which favors small cells) and minimizing the network control associated with handoff (which favors large cells). Four approaches to sharing the spectrum between the two tiers, using per-cell capacity as the measure, are evaluated. The first two feature spread-spectrum sharing, i.e., they use TDMA (time-division multiple access) among microcell users and CDMA (code-division multiple access) among macrocell users (System I), or vice versa (System II). The other two approaches feature orthogonal sharing, i.e., they use TDMA in both tiers, with time slots (System III) or frequency channels (System IV) partitioned so there is no overlap between tiers. Analysis shows that the capacity tradeoffs are poor for Systems I and II because of the large amounts of cross-tier interference: and that System IV gives the best capacity tradeoffs. >

227 citations


Patent
Noach Amitay1
28 Jul 1993
TL;DR: In this article, a priority-based resource assignment procedure for cellular networks is presented. But the priority level is not defined in terms of the quality of service to which a customer subscribes or the particular needs of a subscriber at the time the subscriber is contending for resources, for example, the request for resources may be prompted by a need to make a handoff.
Abstract: Fast resource assignments, especially needed in microcellular network architectures having many fast moving subscribers and high traffic volume, is provided through the use of a priority based resource assignment apparatus and procedure. Part of the communications resources in a cellular network, for example, one carrier frequency and/or one time slot, or particular code division multiple access sequences are dedicated to the execution of the assignment procedure. Available communications resources are auctioned to cellular subscribers contending for resources based upon a level of priority assigned to each contending subscriber. The priority level may be based on such things as the quality of service to which a customer subscribes or the particular needs of a subscriber at the time the subscriber is contending for resources, for example, the subscriber's request for resources may be prompted by a need to make a handoff. The procedure involves an auction period when a determination is made regarding which of a group of contending subscribers has the highest priority level. The procedure then enters a resource assignment period where an available communications resource is actually assigned to the subscriber having the highest priority level. The auction and assignment periods are then repeated for the remaining contending subscribers until there are no longer any contending subscribers or there are no longer any available resources. Fast resource assignment could be used to increase system capacity and efficiency of spectrum utilization through the ability to perform speech activity resource sharing.

160 citations


Journal ArticleDOI
Sanjiv Nanda1
TL;DR: A parametric model based on results from vehicular traffic theory, that applies to vehicles and pedestrians in urban, suburban, and highway cellular systems is proposed, that was found that microcells are unnecessary in urban environments if the pedestrian penetration is small and that an architecture with microcells and overlaid macrocells is required only if a majority of teletraffic is pedestrian generated.
Abstract: As cellular systems evolve into personal communication networks, teletraffic modeling of users will become crucial. Teletraffic models are required for cellular system layout and planning and to evaluate tradeoffs in system design issues. The paper begins with a study of handoff rates in evolving cellular systems. Using simple geometry, it shows that in macrocells with homogeneous traffic the handoff rate per call increases only as the square-root of the increase in the call density. The situation is different in microcells where individual traffic paths become important and the homogeneous traffic model does not apply. Under smooth flow, the handoff rate along a traffic path goes up linearly with the number of new boundaries intersecting the path. Hence, in urban and highway microcells the handoff rate per call increases linearly with increasing call density. It proposes a parametric model based on results from vehicular traffic theory, that applies to vehicles and pedestrians in urban, suburban, and highway cellular systems. The model helps quantify various design tradeoffs. With reasonable parameter values, it was found that microcells are unnecessary in urban environments if the pedestrian penetration is small and that an architecture with microcells and overlaid macrocells is required only if a majority of teletraffic is pedestrian generated. >

148 citations


Patent
Esa Malkamaki1, Harri Jokinen1
22 Jun 1993
TL;DR: In this paper, parallel physical links are formed between the mobile station (MS) and two or more base stations (BTS1, BTS2), whereby these base stations transmit the same signal to the MS in different time slots, and possibly in a different frequency.
Abstract: The soft handover of a channel or a base station according to the invention functions especially well in a TDMA system with a high TDMA milo. For the time of preparation of handover parallel physical links are formed between the mobile station (MS) and two or more base stations (BTS1, BTS2), whereby these base stations transmit the same signal to the mobile station (MS) in different time slots, and possibly in a different frequency.

117 citations


Patent
07 Apr 1993
TL;DR: In this article, a mobile station assists the wireless network with handover from a first base station to a second base station by determining the relative signal strengths of the signals received from the other base stations.
Abstract: A mobile station assists the wireless network with handover from a first base station to a second base station. The mobile station receives transmissions from the first base station using a first spreading code corresponding to the first base station while receiving signals from at least one other base station. The mobile station determines the relative signal strengths of the signals received from the other base stations and reports the relative signal strengths to the first base station to support handover determinations by the wireless network.

105 citations


Journal ArticleDOI
TL;DR: A distributed microcellular architecture based on the IEEE 802.6 Metropolitan Area Network is proposed, and is shown to meet anticipated personal communications service (PCS) needs, and a distributed subscriber database architecture is proposed to facilitate call setup, tracking of roamers and handoffs.
Abstract: A distributed microcellular architecture based on the IEEE 802.6 Metropolitan Area Network (MAN) is proposed, and is shown to meet anticipated personal communications service (PCS) needs. A method is presented to calculate MAN coverage in urban areas, and is used to demonstrate coverage of approximately 50 city blocks per MAN. A distributed subscriber database architecture is proposed to facilitate call setup, tracking of roamers and handoffs. To fully utilize MAN bandwidth, a quick method for the heat stations to switch on/off isochronous slots is proposed to facilitate adaptation to PCS traffic level variations. Call setup and handoff procedures are detailed. The PCS signaling overhead is calculated to be 15% of the capacity required to carry voice traffic. >

99 citations


Patent
26 Nov 1993
TL;DR: In this article, a handover request message (172) is transmitted from the mobile wireless station (30) via the backbone LAN (12) to the first base station (22) thereby updating dynamic filtering databases contained in the base stations (22, 52) and transparent bridges (26, 44).
Abstract: A local area network system (10) includes a wired backbone LAN (12) having a plurality of LAN segments (14, 16, 18) interconnected by transparent bridges (26, 44). A plurality of base stations (22, 52) are capable, of communicating with a mobile wireless station (30). In response to a decision at the mobile wireless station (30) to switch communication from a first base station (22) to a second base station (52) a handover request message (172) is transmitted from the mobile wireless station (30) via the backbone LAN (12) to the first base station (22) thereby updating dynamic filtering databases contained in the base stations (22, 52) and transparent bridges (26, 44) through which the handover request message (172) passes as to the new communication location of the mobile wireless station (30).

99 citations


Patent
09 Sep 1993
TL;DR: In this paper, a handoff measurement priority system was proposed for selecting the best handoff candidate cell at times when the number of neighboring cells that meet the measurement criteria is greater than twelve a measurement list is generated.
Abstract: A method and system for selecting the best handoff candidate cell at times when the number of neighboring cells that meet the measurement criteria is greater than twelve a measurement list is generated. The cells are assigned a handoff measurement priority wherein a handoff priority of zero is assigned to 12-N cells where N is between 1 and 6. A priority of 8 is assigned to the worst N cells. A new measurement list is generated using the 12-N cells and other unreported cells having a higher priority than the N worst cells.

82 citations


Patent
03 Nov 1993
TL;DR: In this article, the authors proposed a method for determining the amount of handovers between base stations by using of dual channel quality thresholds (582, 590) which require a higher quality threshold for establishing communication with a base station and a reduction in channel quality before a handover to a new base station.
Abstract: A handset (24, 25) in a radio communication system (20) determines the quality of a channel (500 and 502) in response to an RSSI signal generated by a receiver (174) in combination with either an eye closure measurement (510) or a bit error rate detected by a CRC codeword in received digital information (502). The battery operated handset is also capable of conserving scanning power while operating in an area having high channel quality (520, 560, 566). The handset also has a method for determining the amount of handovers between base stations (21, 22, 23) by use of dual channel quality thresholds (582, 590) which require a higher quality threshold for establishing communication with a base station and a reduction in channel quality before a handover to a new base station.

80 citations


Journal ArticleDOI
29 Nov 1993
TL;DR: A new analytical model for finding the call blocking probability of a cellular mobile system with directed retry is developed and is more sensitive to the percentage of cell overlap than to the mean path length travelled by a mobile unit.
Abstract: A new analytical model for finding the call blocking probability of a cellular mobile system with directed retry is developed. It can give very accurate results for systems with both uniform and nonuniform traffic distributions. With that, we are able to formulate a second analytical model for obtaining the probability of additional handoffs due to directed retry. Numerical results show that the probability of additional handoff due to directed retry is more sensitive to the percentage of cell overlap than to the mean path length travelled by a mobile unit. In our example of a cellular system with a typical 30% cell overlap the probability of additional handoff is about 0.02. The use of directed retry, therefore, is expected to cause only a minimum amount of additional load in handoff processing and has only a minimal effect on the probability of handoff failure. >

78 citations


Proceedings ArticleDOI
18 May 1993
TL;DR: In this article, the tradeoff between network overhead and diversity advantage of soft handoff in CDMA networks is investigated. And the handoff support requirements for both mobile station and network are assessed.
Abstract: A digital cellular standard using code division multiple access (CDMA) is currently under development in the United States. Computer simulation results on frequency reuse efficiency and sectorization gain, which are essential in assessing reverse link system capacity, are presented. Nonideal sector antenna pattern, log-linear path loss, and log-normal shadowing are considered. Simulation results on soft/softer handoff statistics, which are important in assessing the tradeoff between network overhead and diversity advantage of soft handoff, are presented. The handoff support requirements for both mobile station and network are assessed.

Journal ArticleDOI
N. Amitay1
TL;DR: An architecture for a combined personal, mobile, and (possibly) loop access microcellular communications system in which calls are digitized and packetized is presented and it is shown that, in microcells with delays of 1 mu s, 1080 resource assignments per second are feasible.
Abstract: An architecture for a combined personal, mobile, and (possibly) loop access microcellular communications system in which calls are digitized and packetized is presented. A network of microcells is utilized to communicate with the various subscribers via radio. A fast handoff/resource assignment process is introduced. It is subscriber-controlled and is jointly performed by the subscribers and base station employing the resource auction multiple access (RAMA) algorithm. In this deterministic algorithm, resource utilization is independent of traffic load. Using selected GSM parameters with RAMA, for the purpose of illustration, it is shown that, in microcells with delays of 1 mu s, 1080 resource assignments per second are feasible: and with delays as high as 45 mu s, 216 assignments per second are feasible. >

Proceedings ArticleDOI
29 Nov 1993
TL;DR: The proposed RAP protocol in infrastructured wireless (data) network architectures can be practically implemented with simple hardware and thus well suited for the medium access control protocol for wireless LANs and other personal communication systems.
Abstract: A novel medium access control scheme, randomly addressed polling (RAP), is proposed and studied. RAP used in wireless networks allows that the base stations poll successfully only knowing the active mobile nodes via decentralized control without knowing the exact mobile nodes under coverage. Therefore, RAP can provide seemingless services for wireless (data) networks with good utilization of channel(s), transparent to multiple physical transmission, power efficiency for mobile nodes, and no handoff for data services (soft handoff for time-bounded services). In addition, the RAP protocol in infrastructured wireless (data) network architectures can be practically implemented with simple hardware and thus well suited for the medium access control protocol for wireless LANs and other personal communication systems,. >

Patent
N. Amitay1
28 Jul 1993
TL;DR: In this paper, a cellular switching system and architecture is described in which the switching associated with a call originated within one cell but now serviced within another cell is distributed among base stations which are interconnected with each other through a local area network or a packet switch.
Abstract: A cellular switching system and architecture is described in which the switching associated with a call originated within one cell but now serviced within another cell is distributed among base stations which are interconnected with each other through a local area network or a packet switch. The routing procedure associated with the point of origin for a given call is stored in the memory of a switch of public switched telephone network. As an active subscriber crosses a cell boundary, the switch routes all packets of information for the given call to the originating base station for the duration of the call. Importantly, each base station then forwards each packet to the subscriber's current base station via the local area network or a packet switch. In this manner, the inventive architecture is unaffected by the increased crossing between cell boundaries since the switching associated with those calls not within the range of the initial base station is handled in a distributed manner by each base station via the local area network or a packet switch.

Patent
03 Jun 1993
TL;DR: In this paper, the authors proposed a handover protocol based on the DECT standard, in which the original data and the copy data are stored in a cyclic buffer (SB5) so that the phase shift between the original and copy data is eliminated.
Abstract: A digital radio communication system (1) is known, for example based on the DECT standard, in which radio communication of digital speech or data between primary (BS1) and secondary (MS1) stations takes place via duplex FDMA/TDMA connection. Channel allocation therein is dynamic. If necessary because of the receiving conditions, the secondary station (MS1) can initiate a so-called handover by searching for a free channel offering better receiving conditions. In accordance with the invention, this handover is seamless. Digital speech bursts are exchanged via different time slots (ts) during a number of frames (fr), these being digital speech data and copy digital speech data. After verification that the copy data is valid, i.e. that communication has been established via a free channel, handover takes place. The original data and the copy data are stored in a cyclic buffer (SB5) so that the phase shift (d) between the original data and the copy data is eliminated. Subsequently, the channel via which the original data was transported is released. In one embodiment a speech pointer (SPP) for reading speech freely progresses along the cyclic buffer (SB5) and a radio pointer (RFP), progressing along the buffer (SB5) and controlling the writing of speech bursts, is adapted during handover to the phase shift (d) between time slots involved in the handover.

Patent
29 Oct 1993
TL;DR: In this article, an improved frame structure for use in mobile communications systems utilizing slotted protocols is provided, in which consecutive slots in a frame are assigned to each mobile unit so that the mobile unit transmits to a base station during the first slot and receives a transmission from the BS during the second slot.
Abstract: An improved frame structure for use in mobile communications systems utilizing slotted protocols is provided. According to the present invention, consecutive slots in a frame are assigned to each mobile unit so that the mobile unit transmits to a base station during the first slot and receives a transmission from the base station during the second slot. This frame structure, permits the mobile unit to monitor various frequencies for a longer and more continuous period of time. It is important for the mobile unit to have enough time to monitor frequencies while it is not transmitting or receiving so that base station handoff and interference avoidance handoff techniques can be performed by the mobile communications system. Furthermore, according to the frame structure provided by the present invention, the mobile units can be designed with a standard frequency synthesizer. The improved frame structure also allows channel distortion to be minimized by providing adaptive equalization with transmit precompensation and/or antenna diversity in the base stations.

Patent
Walt Rozanski1, Kamyar Rohani1
26 Jul 1993
TL;DR: In this article, a communication system utilizes rotated bursts of voice channels to implement mobile assisted handoff (MAHO), where mobile stations measure the voice channels of adjacent cells as hopping frequencies are rotated from frame-to-frame of the communication system.
Abstract: A communication system utilizes rotated bursts of voice channels to implement mobile assisted handoff (MAHO). Mobile stations measure the voice channels of adjacent cells as hopping frequencies are rotated from frame-to-frame of the communication system. Measurement of the voice channels of adjacent cells can be performed by mobile stations during timeslots subsequent to their receive and transmission so that measurement during a timeslot dedicated to a control channel related to the adjacent cells is not necessary.

Patent
09 Sep 1993
TL;DR: In this article, a method and system for handing off an on-going communication from a serving cell to a neighboring cell of a cellular communication system having mobile units with a scanning capability is presented.
Abstract: A method and system for handing off an on-going communication from a serving cell to a neighboring cell of a cellular communication system having mobile units with a scanning capability. A dynamic threshold is calculated for effecting the handoff under certain operating criteria. The minimum attenuation level of the mobile unit and the minimum level permitted by a neighboring cell is used in selecting the dynamic threshold.

Patent
Thomas G. Hulsebosch1
23 Apr 1993
TL;DR: In this paper, a radiotelephone system verifies the carrier/interference (C/I) of a selected target channel before handoff, where the channel is keyed (transmitting) and dekeyed (not transmitting).
Abstract: A radiotelephone system verifies the carrier/interference (C/I) of a selected target channel before handoff. The subscriber (125), communicating to a source base-station (130) on a source channel, measures the received signal strength indication (RSSI) of a target channel at a target base-station (135) when the channel is keyed (transmitting) and dekeyed (not transmitting). The subscriber (125) transfers the measurements to a source base-station (130) which determines the ratio of the RSSI with the keyed channel (C) to the RSSI with the dekeyed channel (I). If the ratio is greater than a predetermined threshold, the source base-station (130) transfers the subscriber (125) from the source channel to the target channel at the target base-station (135).

Patent
23 Sep 1993
TL;DR: In this article, a handoff target selection method was proposed for a cellular radio-telephone system where the timing advance of a mobile has exceeded a timing advance threshold, the bit error rate has risen above a BER theshared, or the signal level has fallen below an RSSI threshold.
Abstract: In a cellular radio-telephone system (50), a method of selecting an appropriate handoff target where the timing advance of a mobile has exceeded a timing advance threshold, the bit error rate has risen above a BER theshold, or the signal level has fallen below an RSSI threshold. The method includes discarding signal measurements of inappropriate base sites or base sites at excessive distance and performing calculations on the remaining measurements to select an appropriate handoff target.

Patent
09 Sep 1993
TL;DR: In this article, a method and system for handing off an on-going communication from a serving cell to a neighboring cell of a cellular communication system having scanning receivers associated with each base transceiver station is presented.
Abstract: A method and system for handing off an on-going communication from a serving cell to a neighboring cell of a cellular communication system having scanning receivers associated with each base transceiver station. A dynamic threshold is calculated for effecting the handoff in accordance with various operating conditions. The current mobile minimum attentuation level, (MT) the minimum permissible attenuation level of a serving (MS) cell and a neighboring cell (MN), together with the RF signal strength of the mobile unit at the neighboring cell (RSSI-NBR) and the serving cell (RSSI-SRV) are used in calculating a dynamic threshold (RSSI-THP).

01 Jan 1993
TL;DR: The set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone are described and how they are implemented with the ground segment are described.
Abstract: Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

Patent
Muszynski Peter1
24 Sep 1993
TL;DR: In this article, the authors proposed an inter-exchange soft handoff with diversity combining, where user communications control and signal diversity combining functions involved with the user communications are handed off from a first mobile exchange to a second mobile exchange.
Abstract: In a cellular telecommunications system having mobile exchanges, base stations and user mobile stations roaming in the system, the mobile exchanges are arranged to provide inter-exchange soft handoff with diversity combining. The mobile exchanges further are arranged to provide for control handoff, wherein user communications control handoff, wherein user communications control and signal diversity combining functions involved with the user communications are handed off from a first mobile exchange to a second mobile exchange.

Patent
Rune Goeran1
09 Aug 1993
TL;DR: In this article, a handoff control method for a telecommunications network consisting of a land system and a plurality of mobile stations is presented, where each cell is divided into a first region where evaluation of measurement values is performed and a second region where the evaluation of values is not performed.
Abstract: A method of controlling handoff in a telecommunications network is provided, the network including a land system and a plurality of mobile stations, the land system including a plurality of cells, the method comprising the steps of dividing each cell into a first region where evaluation of measurement values is performed and a second region where the evaluation of measurement values is not performed, performing an evaluation of measurement values when a mobile station enters the first region, and controlling the handoff based on the evaluation of measurement values.

Patent
Esa Malkamaki1, Harri Jokinen1
23 Jun 1993
TL;DR: In this article, parallel physical links (R1,R2) are formed between the mobile station MS and the two base stations (BTS1,BTS2), whereby these base stations transmit the same signal to the mobile Station MS in different time slots and possibly on different frequencies.
Abstract: In preparation of a handover from base station BTS1 to base station BTS2 parallel physical links (R1,R2) are formed between the mobile station MS and the two base stations (BTS1,BTS2), whereby these base stations (BTS1,BTS2) transmit the same signal to the mobile station MS in different time slots and possibly on different frequencies.

Patent
20 Dec 1993
TL;DR: In this paper, a wireless local area network (WLAN) system with a plurality of base stations (16) connected in a wired LAN (12) is described. And the mobile station (20) determines the communications quality of the beacon message (70) for the cell in which it is currently located and if this quality becomes unacceptable, switches to a search mode wherein beacon messages from any base station (16, are received and their communications quality is determined.
Abstract: A wireless local area network system includes a plurality of base stations (16) connected in a wired LAN (12). A mobile wireless station (20) can roam through communication cells (24) defined by the base stations (16). The base stations (16) transmit beacon messages (70) at regular intervals. The mobile station (20) determines the communications quality of the beacon message (70) for the cell in which the mobile station (20) is currently located and if this quality becomes unacceptable, switches to a search mode wherein beacon messages (70) from any base station (16) are received and their communications quality is determined. The mobile station (20) switches to communicate with a base station (16) providing a beacon message (70) with an acceptable communications quality.

Journal ArticleDOI
TL;DR: The universal mobile telecommunication system (UMTS) will implement terminal mobility and a form of personal mobility limited to UMTS, and the application of the intelligent network architecture for the implementation of the UMTS mobility procedures and service provision is assumed.
Abstract: The universal mobile telecommunication system (UMTS) will implement terminal mobility and a form of personal mobility limited to UMTS. The most essential procedures to provide this are related to user registration, location management, handover and security. These mobility procedures are specified using specific functional models. In these models, the required functions are identified and the distribution of the functions in the network is anticipated. In a next step, the specific models are mapped onto a generic functional model. This generic model can be considered as the integration and unification of the specific models. Its structure reflects two important implementation aspects. First, the integration of UMTS into future networks for fixed telecommunications is anticipated. Secondly, the application of the intelligent network architecture for the implementation of the UMTS mobility procedures and service provision is assumed.

Patent
Paavonen Tapio1
29 Nov 1993
TL;DR: In this article, the authors propose a method for operating a TDMA system and measuring adjacent base stations in which dummy time slots are inserted into the TDMA signal sent by a base station, offsetting the time slots of two carriers with respect to each other.
Abstract: A method for operating a TDMA system and measuring adjacent base stations in a TDMA radio system in which dummy time slots are inserted into a TDMA signal sent by a base station. These dummy time slots offset the time slots of two carriers with respect to each other. Therefore, a mobile station locked to a predetermined time slot on one carrier is able to measure and decode any time slot of an adjacent carrier within a longer period of time for a possible handover.

Patent
20 Oct 1993
TL;DR: In this paper, a method for making handover decisions in a radio communication network comprising of fixed base stations and a number of mobile units was proposed. But the handover decision is made whether, or not, a handover will be effected by the network.
Abstract: A METHOD FOR MAKING HANDOVER DECISIONS IN A RADIO COMMUNICATIONS NETWORK The invention relates to a method for making handover decisions in a radio communication network comprising a number of fixed base stations and a number of mobile units. The method utilises an artificial neural network which is an image of the real network of a respective base station and which exhibit a behaviour pattern learnt through the acquisition of information from the network. Thereafter, simulation is carried out in the neural network through the generation of a list of eligible base stations to which handover can be effected, every one of the eligible stations being given points. Thereafter, a decision is made whether, or not, a handover will be effected by the network.

Journal ArticleDOI
TL;DR: This paper proposes an analytical model for the handover in LEO satellite networks that is applied to different network configurations and compared to discrete-time simulations, and results agree with those obtained from the analytical model.
Abstract: The spectacular growth of cellular telephone networks has demonstrated the demand for personal communications. Communication systems based on low earth orbit (LEO) constellations of satellites seem to be an adequate approach to achieve a world-wide network. When defining the capacity in terms of satellite circuits, the network designer has to take into account the handover traffic. Unfortunately, in a LEO communication network where handover is most often due to the network nodes motion, handover traffic models for terrestrial cellular networks cannot be used. Hence specific models must be developed. This paper proposes an analytical model for the handover in LEO satellite networks. This model is applied to different network configurations and compared to discrete-time simulations. Simulation results agree with those obtained from the analytical model.