A method and apparatus for allocating channels in a mobile telecommunications system supporting both packet and circuit switched traffic

(54) NAME Procedure and apparatus for allocating channels in a telecommunications network with both packet-switched and circuit-switched traffic (56) RELEASED PUBLICATIONS:

US Al 5 729 534 (370/280) (57) SUMMARY:

The present invention relates to efficient traffic management in a TDMA system where both circuit-switched and packet-switched traffic occur.

The process according to the invention comprises the following steps:

A maximum number of connections (NUmax) that can be assigned to a channel is specified;

When a packet-switched connection is requested, the following steps are performed:

- it is examined whether the maximum number of channels (TSmax) has been allocated and, if not, the available channels are assigned to the connection;

- if more channels were requested, other channels are allocated among the channels that can be assigned to packet switched connections to the requested packet switched connection.

A control mode in a mobile telecommunications network comprising programs for performing the method is also described.

<img file="SE519730C2_D0001.tif" />

The numbers in brackets indicate international identification code, INID code. Letters in clamps indicate international document code.

<td rowspan="2">'pry code</td><td colspan="3">Patents use the following document codes for their patents</td>

<td>cleartext</td><td>code</td><td>cleartext</td>

<td>A</td><td>widely available patent application</td><td>L</td><td>widely available</td>

<td>B</td><td>pamphlet *</td><td>TI</td><td>translation of the requirements of European patent application</td>

<td>B5</td><td>corrected layout letter *</td><td>T2</td><td>correction of translation of the requirements of European patent application</td>

<td>C</td><td>patent *</td><td>T3</td><td>translation of European patent</td>

<td>Cl</td><td>patent *</td><td>T4</td><td>translation of European patent in amended form</td>

<td>C2</td><td>patent</td><td>T5</td><td>corrected translation of European patentskrift</td>

<td>C3</td><td>rättad patentskrift</td><td>T8</td><td>rättad översättning av europeisk patentskrift</td>

<td>C5</td><td>rättad patentskrift *</td><td>T9</td><td>korrigerad Översättning av europeisk patentskrift</td>

<td>C8</td><td>koaigerad förstasida till patentskrift</td><td></td><td></td>

<td>E</td><td>patentskrift i ändrad lydelse</td><td></td><td></td>

<td>E8</td><td>korrigerad förstasida till patentskrift i ändrad lydelse</td><td></td><td></td>

<td>E9</td><td>rättad patentskrift i ändrad lydelse</td><td colspan="2">* publicerad under äldre lagstiftning</td>

/Nationskoder

<td>.AP</td><td>.African Regional</td><td>CN</td><td>Kina</td><td>KI Kiribati</td><td>RU</td><td>Rvska Federationen</td>

<td></td><td>Industrial Property</td><td>CO</td><td>Colombia</td><td>KM Comorema</td><td>RW</td><td>Ruanda</td>

<td></td><td>Organization (.ARIPO)</td><td>CR</td><td>Costa Riea</td><td>KN St Kitts</td><td>SA</td><td>Saudi-.Arabien</td>

<td>EA</td><td>Euroasian Patent Office</td><td>CU</td><td>Kuba</td><td>KP Dem. Folkrepubliken Korea</td><td>SB</td><td>Salomonöama</td>

<td></td><td>(E.APO)</td><td>CV</td><td>Kap Verde</td><td>KR Republiken Korea</td><td>SC</td><td>Seychellerna</td>

<td>EP</td><td>Europeiska Patentverket</td><td>CY</td><td>Cypem</td><td>KW Kuwait</td><td>SD</td><td>Sudan</td>

<td></td><td>(EPO)</td><td>CZ</td><td>Tjeckiska republiken</td><td>KA’ Cayman-öama</td><td>SE</td><td>Sverige</td>

<td>OA</td><td>African Intellectual</td><td>DE</td><td>Tvskland</td><td>KZ Kazachstan</td><td>SG</td><td>Singapore</td>

<td></td><td>Property Organization</td><td>DJ</td><td>Djibouti</td><td>LA Laos</td><td>SH</td><td>St Helena</td>

<td></td><td>(O.API)</td><td>DK</td><td>Danmark</td><td>LB Libanon</td><td>SI</td><td>Slovenien</td>

<td>WO</td><td>World Intellectual</td><td>DM</td><td>Dominica</td><td>LC Saint Lucia</td><td>SK</td><td>Slovakien</td>

<td></td><td>Property Organization</td><td>DO</td><td>Dominikanska republiken</td><td>LI Liechtenstein</td><td>SL</td><td>Sierra Leone</td>

<td></td><td>(WIPO)</td><td>DZ</td><td>Algeriet</td><td>LK Sri Lanka</td><td>SM</td><td>San Marino</td>

<td>IB</td><td>WIPO(i vissa fall)</td><td>EC</td><td>Ecuador</td><td>LR Liberia</td><td>SN</td><td>Senegal</td>

<td></td><td></td><td>EE</td><td>Estland</td><td>LS Lesotho</td><td>SO</td><td>Somalia</td>

<td>AD</td><td>Andorra</td><td>EG</td><td>Egypten</td><td>LT Litauen</td><td>SR</td><td>Surinam</td>

<td>AE</td><td>Förenade Arabemiraten</td><td>ES</td><td>Spanien</td><td>LU Luxembourg</td><td>ST</td><td>Säo Thomé</td>

<td>AF</td><td>Afghanistan</td><td>ET</td><td>Etiopien</td><td>LV Lettland</td><td>SV</td><td>El Salvador</td>

<td>AG</td><td>Antigua</td><td>FI</td><td>Finland</td><td>LY Libyen</td><td>SY</td><td>Syrien</td>

<td>AI</td><td>Anguilla</td><td>FJ</td><td>Fiji-öama</td><td>MA Marocko</td><td>SZ</td><td>Swaziland</td>

<td>AL</td><td>Albanien</td><td>FK</td><td>Falklandsöama</td><td>MC Monaco</td><td>TD</td><td>Tchad</td>

<td>AM</td><td>Armenien</td><td>FR</td><td>Frankrike</td><td>MD Moldavien</td><td>TG</td><td>Togo</td>

<td>AN</td><td>Nederländska Antillerna</td><td>GA</td><td>Gabon</td><td>MG Madagaskar</td><td>TH</td><td>Thailand</td>

<td>AO</td><td>Angola</td><td>GB</td><td>Storbritannien</td><td>MK Makedonien</td><td>TJ</td><td>Tadzjikistan</td>

<td>.AR</td><td>Argentina</td><td>GD</td><td>Grenada</td><td>ML Mali</td><td>TM</td><td>Turkmenistan</td>

<td>AT</td><td>Österrike</td><td>GE</td><td>Georgien</td><td>MM Mayanmar</td><td>TN</td><td>Tunisien</td>

<td>AU</td><td>Australien</td><td>GH</td><td>Ghana</td><td>MN Mongoliet</td><td>TO</td><td>Tonga</td>

<td>AZ</td><td>Azerbajdzjan</td><td>GI</td><td>Gibraltar</td><td>MR Mauretanien</td><td>TR</td><td>Turkiet</td>

<td>BA</td><td>Bosnien och</td><td>GM</td><td>Gambia</td><td>MS Monsterrat</td><td>TT</td><td>Trinidad och Tobago</td>

<td></td><td>Hercegovina</td><td>GN</td><td>Guinea</td><td>MT Malta</td><td>TV</td><td>Tuvalu</td>

<td>BB</td><td>Barbados</td><td>GQ</td><td>Ekvatorial Guinea</td><td>MU Mauritius</td><td>TW</td><td>Taiwan</td>

<td>BD</td><td>Bangladesh</td><td>GR</td><td>Grekland</td><td>MV Maldivema</td><td>TZ</td><td>Tanzania</td>

<td>BE</td><td>Belgien</td><td>GT</td><td>Guatemala</td><td>MW Malawi</td><td>UA</td><td>Likraina</td>

<td>BF</td><td>Burkina Faso</td><td>GW</td><td>Guinea-Bissau</td><td>MX Mexiko</td><td>UG</td><td>Uganda</td>

<td>BG</td><td>Bulgarien</td><td>GY</td><td>Guyana</td><td>MA' Malaysia</td><td>US</td><td>Förenta Staterna (USA)</td>

<td>BH</td><td>Bahrain</td><td>HK</td><td>Hongkong</td><td>MZ Mocambique</td><td>UA'</td><td>LIruguay</td>

<td>BI</td><td>Burundi</td><td>HN</td><td>Honduras</td><td>NA Namibia</td><td>UZ</td><td>Uzbekistan</td>

<td>BJ</td><td>Benin</td><td>HR</td><td>Kroatien</td><td>NG Nigeria</td><td>VA</td><td>Vatikanstaten</td>

<td>BM</td><td>Bermuda</td><td>HT</td><td>Haiti</td><td>NI Nicaragua</td><td>VC</td><td>St Vincent</td>

<td>BO</td><td>Bolivia</td><td>HU</td><td>Ungem</td><td>NL Nederländerna</td><td>VE</td><td>Venezuela</td>

<td>BR</td><td>Brasilien</td><td>ID</td><td>Indonesien</td><td>NO Norge</td><td>VG</td><td>Jungfruöarna</td>

<td>BS</td><td>Bahamaöama</td><td>IE</td><td>Irland</td><td>NP Nepal</td><td>VN</td><td>Viet Nam</td>

<td>BT</td><td>Bhutan</td><td>IL</td><td>Israel</td><td>NR Nauru</td><td>ATI</td><td>Vanuatu</td>

<td>BW</td><td>Botswana</td><td>IN</td><td>Indien</td><td>NZ Nya Zeeland</td><td>AVS</td><td>Samoa</td>

<td>BY</td><td>Vitryssland</td><td>IQ</td><td>Irak</td><td>OM Oman</td><td>YD</td><td>Syd-Jemen</td>

<td>BZ</td><td>Belize</td><td>IR</td><td>Iran</td><td>PA Panama</td><td>YE</td><td>Jemen</td>

<td>CA</td><td>Kanada</td><td>IS</td><td>Island</td><td>PE Peru</td><td>YU</td><td>Yugoslavien</td>

<td>CF</td><td>Centralafrikanska</td><td>rr</td><td>Italien</td><td>PG Papua Nya Gu INEA</td><td>ZA</td><td>South Africa</td>

<td></td><td>Republic</td><td>JM</td><td>jamaica</td><td>PH Philippines</td><td>ZM</td><td>Zambia</td>

<td>CG</td><td>Congo</td><td>YES</td><td>Jordan</td><td>PK Pakistan</td><td>ZR</td><td>Zaire</td>

<td>CH</td><td>Switzerland</td><td>JP</td><td>Japanese</td><td>PL Poland</td><td>ZAV</td><td>zimbabwe</td>

<td>CI</td><td>iVORY COAST</td><td>KE</td><td>Kenya</td><td>PT Portugal</td><td></td><td></td>

<td>CL</td><td>chile</td><td>KG</td><td>Kyrgyzstan</td><td>PA 'Paraguay</td><td></td><td></td>

<td>CM</td><td>Cameroon</td><td>KH</td><td>Cambodia</td><td>RO Romania</td><td></td><td></td>

519 730

technology Area

The present invention relates to mobile telecommunication networks and in particular to the allocation of channels in such a network when both packet switched and circuit switched traffic is used in the network.

Description of prior art

In many mobile phone systems, e.g. GSM (Global System for Mobile Communication) is a protocol for both circuit-switched and packet-switched communication.

In circuit switched voice systems, one or more physical channels are assigned to each connection. Each channel is assigned only one connection until the information transmission on that connection stops. In GSM there is the HSCSD protocol for high speed circuit switched data (High Speed ​​Circuit Switched Data) which enables the assignment of multiple physical channels to a connection and which is mainly used for transmitting large amounts of data.

In packet-mediated traffic, data communication is often irregular and the information to be transmitted comes in bursts of varying lengths. During a burst, the bandwidth requirement can be very high, while between bursts it is zero. To optimally utilize each channel, a number of packet communication connections often share a number of physical channels.

The channel or channels assigned to a packet switching connection are assigned to a particular connection only when information is transmitted on the connection. The rest of the time, the channel or channels can be used for the other connections assigned to the same channel or channels. The effective transmission rate of each connection is obviously reduced if many connections share the same physical channels. From a user point of view, it is therefore advantageous not to share a channel with other users.

519 730

The circuit-switched connections often transmit numbers, while the packet-switched connections are mainly used for data. The circuit-switched connections must therefore be sent in real-time, while this is not so critical for the packet-switched connections. Therefore, circuit-switched connections are usually given higher priority than packet-switched connections. This means that if the total number of channels requested is higher than the total number of available channels, packet switched connections can be disconnected to enable a circuit switched connection.

Depending on the traffic demand in the cell, the number of channels needed for each type varies with time. Therefore, dynamic allocation of resources between circuit-switched and packet-switched traffic should be possible. Since the total number of channels in a cell is fixed, the number of channels assigned to each type of traffic must be balanced, especially when the total traffic demand in a cell is high.

European patent EP 0 831 669 A2 describes a method for controlling the load in a Code Division Multiple Access CDMA system in which circuit-switched and packet-switched traffic occurs. The number of channels that can be assigned to each type of traffic can be dynamically set depending on the need for each type of circuit switched and packet switched traffic.

The solution described in EP 0 831 669 A2 relates to the overall distribution of resources between circuit switched and packet switched networks. However, it does not involve optimizing the utilization of the channels that can be assigned to each of the two types of traffic.

Object of the invention

It is an object of the present invention to enable efficient traffic management in TDMA systems where both circuit-switched and packet-switched traffic is used.

519 730

Summary of the Invention Thought

This object is achieved according to the invention with a method for assigning channels in a mobile telecommunication system in which packet switched and circuit switched traffic can be used, which method comprises the following steps:

A maximum number of channels (TXMAX) that can be assigned to packet switched connections for each frequency is specified;

A maximum number of connections (NUmax) that can be assigned to a channel is specified; When a packet-switched connection is requested, the following steps are performed:

- it is examined whether the maximum number of channels (TSmax) has been allocated and, if not, the available channels are assigned to the connection;

- if more channels were requested, other channels are allocated among the channels that can be assigned to packet switched connections to the requested packet switched connection.

The object is also achieved with a control mode in a mobile telecommunications network comprising programs developed to perform the procedure.

The method and control mode of the invention ensures that a certain number of channels are always reserved for circuit switched traffic, and at the same time guarantees that a reasonable number of packet-switched connections share each of the channels that can be used for packet-switched connections.

In a first embodiment, it is investigated whether the maximum number of (TSmax) channels has been assigned, whether the maximum number of (NUmax) connections has been assigned to each of the channels that can be assigned to packet switched connections, and if not, the channels are assigned as has the lowest number of connections to the requested connection.

If the maximum number of (NUmax) connections has been assigned to each of the channels, a different frequency is selected.

519 730

According to a second embodiment, it is examined whether the maximum number of (TXMAX) channels has been assigned, whether the maximum number of (NUmax) connections has been assigned to each of the channels that can be assigned to packet switched connections and if not, it is examined whether the requested number of channels can be assigned to the connection and, if so, the channels with the lowest number of connections are assigned to the requested connection. If the requested number cannot be assigned to the connection, another frequency is selected.

In both embodiments, the steps are preferably performed for each frequency according to a priority list until a frequency is found at which the request for the connection can be met, or the last frequency has been examined.

If no frequency is found at which the request for connection can be met, the best possible assignment of channels is made, the connection is denied or the connection is assigned to channels which normally cannot be assigned to packet switched connections.

The maximum number of channels (TSmax) that can be assigned to packet switched connections and / or the number of connections (NUmax) that can be assigned to each channel can be set individually for each frequency. This allows the establishment of a limited number of high bandwidth packet-switched connections without increasing the total number of channels that can be assigned to packet-switched connections.

If a circuit-switched connection is requested for which no channels are available among channels that cannot be used for packet-switched connections, the necessary number of channels that can be used for packet-switched connections is assigned to the circuit-switched connection.

One or more packet switched connections can be disconnected to create free channels for the circuit switched connection.

This ensures that the circuit-switched connections are always given higher priority than the packet-switched connections, which do not require real-time communication.

519 730

Brief description of the drawings

The invention will now be described in more detail with the aid of preferred embodiments and with reference to the drawings, in which Figure 1 shows the communication between a mobile terminal and a base station in a TDMA system;

Figure 2 is a flowchart of the inventive method;

Figures 3A-3E show the use of the method according to the invention for assigning channels to a frequency.

Detailed description of embodiments

Figure 1 shows the communication between a mobile terminal 1 and a base station 3 in a TDMA mobile telecommunication system. A number of channels are transmitted in time slots at the same frequency. In the figure, eight time slots, corresponding to eight physical channels, are transmitted at the same frequency. The base station 3 is controlled by a base station controller 5 through which it is connected to a telecommunications network 7. However, this description only deals with the communication between the mobile terminal 1 and the base station 3.

A circuit-switched connection is assigned to one or more physical channels and occupies that channel or channels alone as long as the connection lasts. A packet switched connection is assigned to one or more physical channels that it shares with other packet switched connections.

The following definitions are used in the discussion below:

NUmax · The maximum number of packet switched connections that can be housed in the same time slot.

TSmax: The maximum number of time slots on a frequency that can be assigned for packet switched connections. If the TSmax criterion is met for a frequency, this means that at least this number of time slots on that frequency are assigned to packet switched connections.

Area:

519 730 ' ^;· Ρ! · Η.! · Ri

The area criterion is met for a particular frequency if there are at least NUmax connections assigned to all channels that can be assigned to packet switched connections at that frequency.

Both NUmax and TSmax can be given different values ​​for different frequencies. This can be used to make the system more flexible. For example, the value of TSmax can be set relatively low for most frequencies, while a few frequencies may have a higher TSmax to enable packet-switched connections with higher bandwidth at these few frequencies.

NUmax and TSmax are used together to determine when a new frequency should be selected for new packet switched connections to be connected. They can be set by the operator and can be changed as the traffic situation changes.

Two fundamental assumptions are made, which are valid for most TDMA systems:

1) A priority order has been set for the allocation of frequencies to circuit-switched, respectively. parcel traffic.

2) If blocking occurs, circuit switched traffic has a higher priority than packet switched traffic. This means that if a higher number of channels than the available number is requested, a channel used for packet-switched connections can be seized in advance to make room for a circuit-switched connection.

If TSmax has different values ​​for different frequencies, different priority lists can be used. E.g. For example, the first frequency examined can always be the frequency for which TSmax equals the requested number of channels.

Figure 2 is a flow chart of the method according to the invention. In the startup situation, all channels are either free or used for circuit-switched connections.

Step S1: A packet switched connection with a number of N channels is requested.

Step S2: The first frequency in the above priority list is selected.

519 730

Step S3: Is the TSmax criterion met for this frequency? If no, go to step S4; if yes, go to step S5.

Step S4: Assign the channels that can be assigned to packet-switched connections and which are not currently assigned any connection at this frequency to the connection. If more channels are requested, go to step S6; otherwise, end the procedure.

Step S5: Is the Area criterion met for this frequency? If no, go to step S6; if yes, go to step S7.

Step S6: Assign the requested number of channels at this frequency to the packet switched connection, or, if the requested number of channels is higher than TSmax, assign TSmax channels. The channels are selected as the channels with the lowest number of connections assigned, among those already used for packet-switched connections. End of procedure.

Step S7: Is this the last frequency in the priority list? If yes, go to step S8; Om no, go to step S9.

Step S8: Make the best possible assignment of channels.

Step S9: Select the next frequency in the priority list as the current frequency. Go to step S3.

In step S8, i.e. if the TSmax and Area criteria are met for all frequencies, alternative measures are possible. In the flowchart it has been assumed that the connection is assigned to channels that already have more than NUmax connections assigned. It would also be possible to completely deny the connection, in order to guarantee a minimum bandwidth for each connection actually connected. A third possibility would be to assign channels that would not normally be used for packet-switched channels to the connection.

Figures 3A-3E show the assignment of channels according to the procedure described above. In these figures, TSmax has been set to four and NUmax has been set to three. This means that of the eight available channels at the frequency shown, four can be assigned to pa519,730 chain-switched connections. Three connections can share a physical channel before considering assigning a new requested connection to a new frequency.

Figure 3A shows the situation in which there is only one connection on the frequency. Two channels have been assigned to the connection, as shown by the two boxes shaded with diagonal bars.

Figure 3B shows the situation after a second connection has been connected. Three channels have been assigned to this connection as shown by three squares shaded with vertical bars. Because a lower number than TSmax (i.e., four) channels were assigned to packet-switched data before this connection was connected, the connection uses the two channels not previously used and shares a channel with the first connection.

Figure 3C shows the situation after establishing a third connection using three time slots. Since all four channels assigned to packet-switched connections had already been allocated, it was examined whether the Area criterion was met, ie. if the maximum number of connections had already been assigned to each channel. Since this was not the case, all four channels on the frequency that can be assigned to packet-switched connections have been assigned to the connection through the dotted boxes.

Figure 3D shows the situation after two additional single channel connections have been assigned. The time slots used are shown as black boxes. Now all channels except one have been assigned the maximum number of connections.

If a request for a connection with two or more channels is made at this stage, there are two options:

1) The connection is connected at this frequency, which means that on two channels there will be more than NUmax (ie three) connections. This is the situation shown in Figure 3E.

2) Another frequency can be selected for the new connection because it cannot be connected to this frequency without violating the Area criterion.

519 730

The functions described above can be realized as software packages included in a node in the network. A separate node can be included or the features can be implemented in an existing node, e.g. the base station controller 5 shown in Figure 1.

519 730