GB2419498A - A method of allocating timeslots for a packet switched connection in parallel to a circuit switched connection. - Google Patents

Abstract

A method for allocating timeslots for a packet-switched connection to a mobile station in a time-division multiple access communication system, having a repeating cycle of frames each divided into timeslots, concurrently with a circuit-switched connection occupying fixed timeslots in uplink and downlink channels, the method comprising: ```constructing an uplink ordered list of timeslots and a downlink ordered list of timeslots according to a predetermined rule; ```transmitting an identification value in a given timeslot to signal the allocation of assigned slots to said mobile station; ```wherein when said mobile station detects an identification value assigned to it in a timeslot at position i in said ordered list, said mobile station may cease to monitor all timeslots in the downlink ordered list at positions before i in the downlink ordered list for data transmissions and begins to transmit on all timeslots in the uplink ordered list at positions up to and including i. The method can be applied to mobile stations of DTM multislot classes 6, 7, 10 to 12, 32 to 34 and 37 to 39, as defined in 3GPP TS 45.002 Release 6.

Description

N9221 5 GB JGL 1 241 94 98 Method of Allocating Tmeslots in a Packet-

Swltched Circuit In a Mobile Communication System, Mobile Station, Base Station and Computer Program The present invention relates to methods of controlling slot assignment and allocation for packet-switched circuits in a time division multiple access (TDMA) commumcaton system, to base stations and mobile stations using the method and to computer programs for Implementing the mventon. ; GSM is a mobile communucations system employing frequency and time division multiple access (FDMA & TDMA) techniques as well as a cellular structure that can carry both voice signals and data, using a system known as GPRS. To operate the TDMA scheme, time in the GSM system is divided into a repeating structure of frames with each frame comprising 8.....

tmeslots. For convenience, the beginning of each frame in the uplmk, that IS the channel for., . - communication from a mobile station to a base station begins 3 timeslots after the beginning of the corresponding frame on the downlink, that is the base to mobile station channel. This arrangement IS shown in Figure 1 of the accompanying drawings. (It should be noted that the actual time at which a give mobile station transmits may be advanced from the time defined by....

the frame structure by an amount known as the timing advance, TA, which is determined - . . according to the distance between the mobile station and the base station from time-to-time. For simplicity, this aspect of the GSM system IS disregarded below.) As is well known, four TDMA frames are grouped in a radio block.

Voice commumcattons in GSM are carried on a ''arcult-switched'' basis whereby one timeslot per frame on a given radio channel is allocated to the downlnk to a given mobile station and the correspondingly numbered tlmeslot on a corresponding radio channel is allocated to the plink from that same mobile station for the entire duration of a call, irrespective of whether there Is data to be transmitted at a given time. (Comfort noise may be transmitted in the event that one half of the conversation IS silent). The combination of one downlink slot and one uplmk slot per frame IS referred to as a full-rate traffic channel or TCH/F; a half-rate traffic channel or TCH/H comprising one uplmk and one downlmk slot every alternate frame may also be defined and used for voice commumcaton. The constant time relationship between packets of data aids reconstruction of the voice signal.

N92215 GBJGL 2 GPRS IS an extension of GSM that enables data communication earned out on a packet-switched'' basis whereby one or more slots in the unlink and downlmk are assigned to a mobile when a GPRS connection is established for potential use for data transmission but assigned slots are allocated for actual use on a frame by frame basis according to the level of traffic on the network and whether or not data is waiting to be transmitted to or by the mobile station. It allows an increased data rate during packet data transfer by using more than one tmeslot either for transmission or reception. For example, Figure 2 of the accompanying drawings illustrates a GPRS system where two slots are used for transmission and one for reception. The allocation of slots is controlled by the network (base station) and various schemes (referred to as MAC modes) are defined: fixed allocation, exclusive allocation, dynamic allocation and extended dynamic allocation. The later mode (described in GB-2,398,708-A) alms to assign multiple tmeslots per frame in a flexible manner to make maximum usage of the capability of the mobile station, which is determined, among other thmgs, by the rapidity with which the mobile station can "turnaround" from receiving to transmitting and vice versa. ....

The turnaround time is determined, among other thmgs, by the ability of the mobile . . station to retune and stabillse its internal oscillator to match the different frequencies for transmission and reception and also by the need to perform adjacent cell signal level ' measurement. The 3GPP standards define various multislot classes for mobile stations according to their turnaround times and ability to use multiple slots per frame. For each multislot class, ....

certain performance characteristics are defined: - . . Rx - the maximum number of slots per frame in which the mobile can receive; Tx - the maximum number of slots per frame in which the mobile can transmit; Sum the total number of slots per frame In whuch the mobile can transmit or receive Tta - the number of slots required by the mobile to perform adjacent cell signal level measurement and get ready to transmit; To - the number of slots required by the mobile to get ready to transmit without performing adjacent cell signal level measurement; Tra - the number of slots required by the mobile to perform adjacent cell signal level measurement and get ready to receive; Trb - the number of slots required by the mobile to get ready to receive without performing adjacent cell signal level measurement.

Where a mobile station is capable of transmitting and receiving on more than one tmeslot per frame, it would be desirable for a mobile station to be able to perform data transmissions at the same tune as a voice transmission - known as a class A service. Figure 3 of N92215 GBJGL 3 the accompanying drawings shows an example of simultaneous use of clrcutswitched and packet-switched connections. A so-called dual transfer mode (DTM) is defined for GSM/GPRS which makes use of the MAC modes known for GPRS. Unfortunately, DTM does not allow the mobile's full capability to be used In conjunction with dynamic channel allocation (which is an important case smce dynamic allocation allows sharing of resources between different mobiles).

In particular the 3GPP standards do not permit any configuration of tmeslots that allows mobiles of certain muluslot classes (for example class 12 mobiles) to be dynamically allocated the maximum number of unlink slots "Tx" Which they are capable of transmitting (although by using a static, exclusive allocation flus is permlttedj. Therefore the standards unnece-ssanly restrict the I O maximum amount of uplmk bandwidth that can be dynamically allocated to the mobile, to less than the mobile's actual capability.

It should be noted that the above descnpoon of GSM and GPRS is a considerable sunplificaton and additional information as to the operation of these systems is to be found In the various 3GPP standards available from the 3rd Generation Partnership Project .

(ww\v.3g?p.or. Particularly relevant specifications are: 3GPP TS 45.002, 3GPP TS 44.060, . ..

3GPP TS 44.018 and 3GPP TS 43.055. A useful primer and history of the early developments of GSM is "The GSM System for Mobile Commumcations" by M Mouly & M-B Pautet (ISBN 2- 9507190-0-7).

- ..

- .- It IS an aim of the present invention to provide a method of allocating tmeslots in a - tme-dvlslon mulfiplc access communication system when providing circuit- switched and packet- switched connections to the same mobile stanon concurrently.

Accordmg to there IS provided a method for allocating timeslots for a packet-switched connection to a mobile stanon in a tme-dvision multiple access communication system, having a repeating cycle of frames each divided into timeslots, concurrently with a crcuit-swltched connection occupying fixed timeslots in uplink and downlink channels, the method comprising: consnucfing an uplmk ordered 11st of tmeslots and a downlmk ordered list of timeslots according to a predetermined rule; transmitting an identification value in a given tmeslot to signal the allocation of assigned slots to said mobile station; wherem when said mobile stanon detects an ldenuficanon value assigned to it in a tmeslot at position in said ordered list, sand mobile station need not monitor all timeslots in the downltnk ordered list at positrons before in the downlink ordered list for data Transmissions and beams to transnut on all tneslots in the uplulk ordered list at positions up to and nlcludu1g'.

N92215 GBJGL 4 Wlth the allocation system of the present invention, the full capabilities of certain mult- slot classes of mobiles can be exploited for packet-switched data transmissions, that IS a connection occupying dynamically allocated tmeslots, concurrently with a circuit-switched connection, that is one occupying a fixed timeslot per frame. The invention thereby overcomes the special problem of the fixed position of the CS slot tang. The allocation scheme of the present Invention may be referred to as ''Special Extended Dynamic Allocation " (SEDA), which is similar in some respects to Extended Dynamic Allocation (EDA) as defined for GPRS, but has a novel slot allocation rule.

The present invention may advantageously be applied to mobiles of multislot classes 3, 6,7,10tol2,31 to34and36to39.

The present invention will be described further below with reference to the following description of exemplary embodiments and the accompanying schematic drawings, in which: - Figure 1 Illustrates the time slot structure used In GSM; , . - Figure 2 illustrates transmission on multiple time slots in GPRS (packet-switched 2 . commumcatlon); - Figure 3 illustrates simultaneous clrcut-switched and packet-switched communication (Dual Transfer Mode) In GSM/GPRS; - Figure 4 IS a key for Figures 5 to 7; .

- Figures 5 to 7 illustrate possible multslot configurations according to an embodiment of the Invention of dual transfer mode for Various multislot mobile stations; - Figure 8 illustrates a mobile communication system according to an embodiment of the Invention; - Figure 9 is a flow chart of the construction of an uplmk ordered list used in an embodiment of the Invention; - Figure 10 IS a flow chart of the construction of a downlmk ordered list used In an embedment of the Invention; - Figure 11 is a flow chart of the construction of an uplmk ordered list used in another embodiment of the invention; and - Figure 121S a flow chart of the construction of a downlink ordered list used In another embodiment of the invention.

In the drawings, like elements are designated by like references.

N92215 GB]GL 5 In an embodiment of the invention, rules are defined for the dynamic allocation of unlink and downlmk slots In a packet-switched connection with a mobile station having multi- slot capabilities concurrently with a clrcult-swltched connection. For the sake of economy, only relevant details of a communication system embodying the invention will be described below, further information can be obtained from the references given above.

As shown m Figure 8, a GSM/GPRS mobile communication system comprises a base transceiver station BTS which communicates via radio With a plurality of mobile stations MST, MS2. The base transceiver station is connected to a base station controller BSC, which in turn is connected to a wider communications network, such as a PSTN, ISD.N or therInternet. The division of functions between BTS and BSC is not relevant to the present invention and the two are together referred to as a base station below. The mobile stations may receive and initiate voice calls from and to other mobile stations In the same or other communications systems as well as fixed terminals in the PSTN or ISDN networks. Data connections may also be made to connect the mobile station to the Internet or another communications network, e.g. to allow collection and transmission of email or browse WAP or WWW sites via the Internet. A voice.' . call is earned over a circuit-switched connection CS1 or CS2 between the mobile station and the base station whilst a data connection Is made over a packet-switched connection PS. In a so- called Class-A or Dual Transfer Mode, a crcult-swltched connection CS1 and a packet-switched connection PS are made concurrently with a single mobile station MST. . as. .e

The mobile commumcaton system operates on a repeating frame structure, shown In - of..

Figure 1, In which radio channels are divided Into frames, each frame comprising 8 tmeslots of equal length numbered O to 7. This shows the frame from the point of view of the mobile stations, in that uplmk slots are designated tx for transmit and downlink slots rx for receive. The frames of radio channels designated for uplink, that is from mobile station to base station, commumcation begin three timeslots later than those designated for downlink communication.

It should be noted that the tmmg relationship between up and downlink frame structures is defined at the base station BTS; a mobtlc station will transmit ahead of Its slot by an amount known as the tirrung advance TA which is determined dynamically In order to ensure that the burst transmitted by the mobile station arrives at the base station in its correct slot. This aspect of the system IS well known and will not be discussed further below.

When a voice connection IS established to a mobile, the mobile station is allocated a full- or half-rate traffic channel TCH/F or TCH/H. A full-rate traffic channel TCH/F comprises one tmeslot per frame In the downlmk radio channel and the correspondingly numbered timeslot in the corresponding upllk radio channel. These slots are allocated to, and used by, the mobJe N92215 GBJGL 6 station throughout the duration of the call, so that the mobile always receives and decodes data in the allocated downlmk slot and always transmits data in the allocated uplink slot. Comfort noise may be transmitted in the event that either half of the conversation is silent. A half-rate traffic channel comprises one downlnk tmeslot and the correspondingly numbered uplink tmeslot in every alternate frame. In both cases there is a fixed timing relationship at the base station between signal bursts in the up and downlinks.

If the mobile station has multislot capabilities - that is its ability to turnaround from transmission to reception and vice versa, the speed with which it can perform adjacent cell signal level measurement, its power supply and its processing speed are such that it is capable of transmitting and or reccivmg in more than one tmeslot per frame - then a packet-sw1tched connection may be made concurrently with the circutswitched connection, as shown in Figure 3.

A packet-sw1tched connection differs from a circuit-sw1tched connection in that although one or more downlink and/or uplink slots are assigned to the mobile station for ^ potenua1 use, they are not actually allocated for use unless there is actually data to be transmitted ' . The allocation of slots is controlled by the base station and takes account of network traffic and in particular the demands of other mobiles that may also have been assigned the same slots in the.

same channels. Methods for the mobile station to signal that it requires uplink bandwidth and for dividing the available slots between mobile stations are known and will not be described.

further herem. - a.

In the prior art, when a packet-switched connection is bemg established, the base station sends to the mobile station a umeslot assignment message. This message identifies the timeslots in the up and downlinks that are allocated to the mobile station and provides and identification code for each timeslot. The identification code is known as a USF and may take one of eight values, allowing up to eight mobile stations to be assigned each slot. Different USF values may be assigned for each assigned timeslot. Timeslots may be assigned as full-rate packet data channels, referred to as a PDCH/F, in which the assignment IS of the nmeslot of that number in every frame. They may also be assigned as half-rate packet data channels, a PDCH/H, in which the assignments is of a given numbered timeslot in every alternate tmeslot. Thus, the significance of a specific value taken by the USF depends on the umeslot in which it resides. In general, the value of the USF indicates two things: (1) it 1denufies a mobile, if any, to which certain uplink resources will be allocated during the next radio block N92215 GB]GL 7 (2) It identifies which uplmk resources will be allocated to the identified mobile (if any is identified).

Note that way in which the identified mobile determines the uplink resource is dependent on factors specific to the identified mobile, including the allocation mode of the mobile, the multislot class of the mobile and the currently assigned PDCHs. Existing allocation modes defiecd in the GSM standards Include fixed allocation, dynamic allocation, exclusive allocation and extended dynamic allocation.

The mobile station then momtors the assigned downlmk tmeslots to detect, in a s1gnallmg part of the burst, a matching USF. For example, if mobile station MS1 has been assigned slot O and given a USF value for that slot of 5, then if mobile station MS1 detects the USF value 5 broadcast in downlink slot 0, it determines that a matching USF IS detected. The detection of the matching USF and the timeslot in which it is detected signals to the mobile station which tmeslots in the uplmk it should use to transmit data.

To increase the number of packet channels that can be used by a mobile operating in.' ' DTM, the present invention decouples the USF from the corresponding downlmk slot number. ,, . In other words, the downlmk timeslot number on which USF_TNx appears is no longer v, restricted to tmeslot x. The multislot class, the slot number allocated for the circuit switched call, and a set of ordering rules, and example of which is defined below, allow both the network and the mobile to construct the same slot ordering sequences (one sequence for the order of, . activating uplmk slots, and one for the downlink slots on which the corresponding USFs will -, e.; . appear). These orderings are dependent on multislot class and the CS timeslot number. The rules of the invention apply to the following multislot classes: 6, 7, 10, 11, 12, 32-34, 37-39. The mobile station may indicate its capability of operating according to the method of the invention to the network.

SEDA will have to be explicitly enabled when uplmk slots are assigned if it IS to be applied to assignments that are currently possible without SEDA. Alternatively, SEDA can be Implicit if a given assignment IS not possible with existing allocation methods.

The present invention provides rules to define DL/UL mapping Implicitly In both NW and MS, based on Information available to both. This allows for a dynamic yet unambiguous allocation of maximum possible resources in Dual Transfer Mode.

In the following text, the Circuit Switched (CS) timeslot number Is called NCS.

Firstly, an ordered set of numbers called the 'qplink PDCH ordered list is specified. This corresponds to the set of uplmk PDCH numbers that the mobile can potentially be assigned in SODA.

N92215 GB]GL 8 The uplznk PDCH ordered list shall be contained within a contiguous range of integers i such that lo≤ i≤ hi, where: 0≤ lo≤h≤7, (1) and hi-lo ≤ Tx. (2) where Tx is the maximum number of transmit slots allowed by the MS multslot class.

Tx_max is related to the maximum number of uplmk PDCHs that can be assigned for a given multtslot class in DTM and is given by the following equation: Tx_max = max(O,mn(Sum-3, Tx-1)) (3) The creation of the Splint PDCH orderedlirtls shown in Figure 9 and involves the following steps: 1) Intialise the plink PDCH ordered IZJI to the empty set, 1.e. contatrung no elements.

2) Construct the right hand set of lusty uplink tmeslots for potential allocation (see below).

3) Modify the Plink PDCH ordered Izst if half rate CS 1S used (see below).

The right hand set contains tmeslots with the ordered 11st given below t; ' INGs +1, NGS +2, NGS +3, , NGS A] (9 This set is constructed by adhering to the following rules: 1. The slot number NCS +j 1S less than or equal to 7.

2. The Tra must be respected by slot number NGS +} and the CS receive slot NCS in the next TDMA frame. . I. 3. With this set appended to the Plink PDCH ordered list, the total number of slots in the set are no more than Tx_max The right hand set is appended to the Plink PDCH ordered lift If the half rate CS IS used then the uplink PDCH ordered list IS modified by adding NGS -1 to the end of the list, hence the final list will contain: [NCS +1, NCS +2, , NGS +}, NCS -1] (5) Next, an ordered set of numbers called the 'downlznk 1'DCH ordered Izst' IS specified. This corresponds to the set of downlink PDCHs that the mobile can potentially monitor for USF in SEDA.

The downlznk PDCH ordered list shall be contained within a contiguous range of integers go, hi) where 0≤ lo≤hi≤7, and hi-lo ≤ Rx.

The maximum number of tmeslots monitored on the downlink for USE is Tx_max as defined before.

The creation of the downlznk PDCH ordered Izst IS shown in Figure 10 and involves the following steps: N9225 GBJ<4 9 1. Intlaltse the downlnk PDCH ordered list to the empty set, i.e. containing no elements; 2. Add the slot NCS +1 to the downlmk PDCH ordered list; 3. Construct the left hand set of q tmeslots for potential USF monitoring (see below); 4. Reverse the downlnk PDCH ordered list (see below); 5. Modify the downlink PDCH ordered list if half rate CS is used (see below); If the downlnk l'DCll ordered list contains fewer than lx_max numbers, then numbers from the beginning of the following sequence (the 'receive left hand.ret,) are appended to the downlnk PDCH ordered list until either it contains Jx_max numbers or all numbers in the left hand set have been used: i The receive left band set contains timeslots with the ordered list given a below: [Ncs -1, Ncs -2, NCS -3, , NcS-q] (6) This set Is constructed by adhering to the following rules: . :.

1. The slot number Ncs-q is greater than or equal to 0. e 2. The Ttb must be respected by slot number Ncs-q and the CS transmit slot NCS In the - previous TDMA.

3. With this set appended to the downlznk PDCH ordered fist, the total number of slots In the set is no more than Tx_max.

The final ordered set is reversed and called the downl2nk PDCH ordered list.

[NCS-q, , NCsl' NCs+l] (I If half rate CS Is used then slot NCS Is appended at the end of the downlznk PDCH ordered lst, hence the final list will contain: [Ncsq, , Ncs1, Ncs+1, Ncs] (8) In the method of the present Invention, the USF of an assigned uplink PDCH that occurs at position in the uplink ordering can be momtored on the ith PDCH In the downlink PDCH ordering.

Uplmk PDCH ordered list: [Ncs+l, , Ncs+i] (9) Downlmk PDCH ordered list: [Ncsq, , NCS-1, NCS+1] (10) The elements in the Plink l'DCH ordered lest and downlink PDCH ordered list are numbered consecutively starting from 1. The first element In the list has index 1 and the next element has index 2 and so on.

In operation, the mobile station shall momtor for a USF In downlink PDCHs contained in the downlink PDCH ordered list.

The mobile station shall search for a matching USF on all the PDCHs in the downlink PDCF] ordered l.rt whose Index In that list corresponds to the 1ndcx of an assigned PDCH In the N9221 GB GL 1 0 Plink PDCH ordered Izst. If it finds a matching USF at position z in the downlink PDCH ordered Izst, then in the subsequent radio block (or group of 4 radio blocks) It need not monitor downlink PDCHs that have a posluon lower than i in the downlink PDCH ordered list, but shall attempt to monitor downlink PDCHs at position z or higher In the downing l'DCH ordered Izst.

If the CS channel is full rate, In the subsequent radio block (or group of 4 radio blocks) it shall transmit on all assigned PDCHs that have a position lower than or equal to i In the Unlink PDCH ordered Izst.

If the CS channel Is half rate, in the subsequent 2 radio blocks (or group of 4 radio blocks) it shall transmit on all assigned PDCHs that have a position rawer than or equal to i In the Plink PDCH ordered Izst. If the mobile station is polled on the half rate channel, then the mobile station may send a poll response on one of the uplmk assigned tmeslots.

Table 1 below shows the result of applying the rules defined In this document to a MS that IS capable of transmitting on 5 slots, for example class 34. The uplnk CS tmeslot NCS is. . never used for packet data. The bottom row and rightmost column are only applicable If a half rate CS is resource IS assigned. The table shows the of the uplznk ordered Izst (contained In top row) and the downlink ordered Izst. (contained in left hand column). The ticks in a horizontal row show the uplmk PDCHs on which the mobile station can transmit if a USF is found on the.

downlink PDCH at the left of that row. .... - -

Table 1

_ Transmit Slot l\ Ncs+l NCs+2 NCS+3 Ncs-l USF Ncs- 1 Slot Ncs / As _ Figures 5, 6 and 7 show example allocations using the method of an embodiment of the rventon,F1gure 4 gives a key to these figures.

An alternative embodiment of the Invention styluses a modification of the above rules, as described below.

The creation of the Plink PDa-] ordered Izst IS shown in Figure 11 and Involves the following steps: 1. Initialize the Plink PDCH ordered list to the empty set, i.e. containing no elements.

2. Add the slot NCs -1 to the uplink PDCH ordered list.

3. Construct the right hand set of listj uplnk tmeslots for potential allocation (see below).

The right hand set contains umeslots with the ordered list given below N92215 GB JGL 1 1 [Ncs +1, NO +2, , Ncs +l] (11) This set is constructed by adhering to the following rules: 1. The slot number NCS +j is less than or equal to 7.

2. Tra must be respected by slot number NCS +j and the CS receive slot Nc5 in the next TDMA frame.

3. With this set appended to the zplznk PDCH ordered list, the total number of slots in the set are no more than Tx_max The right hand set 1s appended to the Plink PDCH ordered list and hence the final list will contain: S [Nc5 -1, NCS +1, NCS +2, , Ncs +] (12) The creation of the downing PDCH ordered list 1S shown in Figure 12 and involves the following steps: 1. Intiallse the downlnk PDCH ordered list to the empty set, i.e. containing no elements. a.

2. Construct the left hand set of q timeslots for potential USE monitoring (see below) 3. Reverse the downlnk PDCH ordered list (see below) 4. Modify of the downlnk PDCH ordered 11st if half rate CS IS used (see below) If the doweling PDCH ordered Izst contains fewer than Tx_max numbers, then numbers. . from the beginning of the following sequence (the 'receive left hand set') are appended to the. . . downing PDCH ordered list until either it contains Tx_max numbers or ah numbers in the left hand set have been used The receive left hand set contains tmeslots with the ordered 11st given below: [Ncs -1, Ncs -2, Nits -3, , NCS q] (13) This set is constructed by adhering to the following rules: 1. The slot number Nc5 -q is greater than or equal to 0.

2. Ttb must be respected by slot number NCS -q and the CS transmit slot NCs in the previous TDMA.

3. The total number of slots in the set is no more than Tx_ max.

The final ordered set IS reversed and called the downlink PDCH ordered Izst [Ncs q, , Ncs -1] (14) If half rate CS is used then slot NCS is appended at the end of the downlznk PDCH ordered Izst, hence the final list will contain: [NCS -q, , Ncs -1, Ncs] (15) In this embodiment, the rules about USF monitoring and the relationship to the uplmk tn1leslots Is exactly same as in the first embodiment.

N92215 GBJGL 12 Table 2 below shows the result of applying the alternative rules defined In this document to a MS that is capable of transmitting on 5 slots, for example class 34. The Spunk CS timeslot NCS is never used for packet data. The bottom row is only applicable if a half rate CS resource is assigned. The table shows the zplnk ordered list (contained in top row) and the downlznk ordered fist (contained in left hand column). The ticks In a horizontal row show the up]ink PDCH on which the MS can transmit if a USE IS found on the down]ink PDCH at the left of that row.

Table 2

Transmit Slot _cs -3 Ncs -I Ncs +l Ncs +2 Ncs +3 USE Ncs -2 l slot Ncs-I _ :-... 10The method of the Invention can be applied to mobile stations of DTM

multslot classes 6, 7, 10 to 12, 32 to 34 and 37 to 39, as defined in 3GPP TS 45.002 Release 6. The capabilities of these classes are set out in Table 3 below: .

Table 3 -.

Muitislot Maximum number of slots Minimum number of slots Type 6 Rx Tx Sum T. T. - 1 . 7. 3 3 4 3 1 3 1 1 _ 11 4 2 5 3 1 2 1 1 12 4 4 5 2 1 2 1 1 32 5 3 6 2 1 1; 1 1 34 -- 66 1- 1- 37 5 3 6 2 1 1 +to 1 1 339 6 4 = 1-1+0 1 1 Rx: Rx describes the maximum number of receive tmeslots that the MS can use per TDMA frame. The MS must be able to support all integer values of receive TS from O to Rx (depending on the services supported by the MS). The receive TS need not be contiguous. For type 1 MS, the receive TS shall be allocated within window of size Rx, and no transmit TS shall occur between receive TS within a TDMA frame. Tx:

Tx describes the maximum number of transmit tmeslots that the MS can use per TDMA frame. The MS must be able to support all integer values of transmit TS from O to Tx N92215 GBJGL (depending on the services supported by the MS). The transmit TS need not be contiguous. For type 1 MS, the transmit TS shall be allocated within window of size Tx, and no receive TS shall occur between transmit TS withm a TDMA frame. Sum:

Sum is the total number of uplink and downlulk TS that can actually be used by the MS per TDMA frame. The MS must be able to support all combinations of integer values of Rx and Tx TS where 1 ≤ Rx + Tx ≤ Sum (depending on the services supported by the MS). Sum Is not applicable to all classes. To:

Tta relates to the time needed for the MS to perform adjacent cell signal level measurement and get ready to transmit.

For type 1 MS It is the minimum number of timeslots that will be allowed between the: ' ' end of the previous transmit or receive TS and the next transmit TS when measurement IS to bet .

performed between. It should be noted that, in practice, the minimum time allowed may be reduced by amount of timing advance. . For type 1 MS that supports extended TA, the parameter Tta is Increased by 1 if TA > 63 and there is a change from RX to TX. ... . For type 2 MS If IS not applicable. . i T. tb Ttb relates to the time needed for the MS to get ready to transmit. This minimum requlremcut will only be used when adjacent cell power measurements are not required by the service selected.

For type 1 MS It IS the mmimum number of timeslots that will be allowed between the end of the last previous receive TS and the first next transmit TS or between the previous transmit TS and the next transmit TS when the frequency is changed In between. It should be noted that,, In practice, the minimum time allowed may be reduced by the amount of the timing advance.

For type 1 MS that supports extended TA, the parameter Ttb = 2 if TA > 63 and there IS a change from RX to TX.

For type 2 MS It is the minimum number of timeslots that will be allowed between the end of the last transmit burst In a TDMA frame and the first transmut burst In the next TDMA frame.

N92215 GBJGL

T rat

Tra relates to the time needed for the MS to perform adjacent cell signal level measurement and get ready to receive.

For type 1 MS it is the minimum number of timeslots that will be allowed between the previous transmit or receive TS and the next receive TS when measurement is to be performed between.

For type 2 MS it is the mmlmum number of tmeslots that will be allowed between the end of the last receive burst in a TDMA frame and the first receive burst in the next TDMA frame.

An MS, except for multslot class 30 - 45, shall be able to decode SCH from a nelghbour cell, independent of its relative timing, using an idle frame in combination with Tra . from the preceding frame.

T. :. .

rb. ce Trb relates to the time needed for the MS to get ready to receive. This minimum. . e requirement will only be used when adjacent cell power measurements are not required by the.

service selected.

For type 1 MS it is the minimum number of tmeslots that will be allowed between the previous transmit TS and the next receive TS or between the previous receive TS and the next..

receive TS when the frequency is changed in between.

For type 2 MS it is the minimum number of timeslots that will be allowed between the end of the last receive burst in a TDMA frame and the first receive burst in the next TDMA frame.

It will be appreciated that the above description of exemplary embodiments is intended to be illustrative not imitative. The invention may be embodied in other forms and 1S defined in the appended claims. Computer programs to implement the method of the invention in a mobile station or base station can be written in any suitable language, given the teachings set out above.

Claims (22)

N92215 GBJGL 15 CLAIMS

1. A method for allocating tmeslots for a packet-switched connection to a mobile station in a tme-dvision multiple access communication system, having a repeating cycle of frames each divided Into timeslots, concurrently with a arcult-swltched connection occupying fixed tmeslots in uplink and downlnk channels, the method comprising: constructing an uplmk ordered 11st of tmeslots and a downlnk ordered 11st of umeslots according to a predetermined rule; transmitting an identification value 1n a given tmeslot to signal the allocation of assigned slots to said mobile station; wherein when said mobile station detects an identification value assigned to it in a tmeslot at position z in said ordered 11st, said mobile station may cease to monitor all timeslots imp the downlnk ordered 11st at positions before z in the downlink ordered list for data transmissions .

and begins to transmit on all tlmeslots In the uplnk ordered list at positions up to and Including z.

2. A method according to claim 1 wherein data of a plurality of frames IS combined to form a radio block and changes in allocation of timeslots are applied in the radio block after the, as, radio block In which said Identification value IS transmitted. .

3. A method according to claim 2 wherein the mobile station transmits In timeslots determined by the position of the detected Identification value for the next radio block If the circut-swltched connection occupies one time slot in the uplmk and downlnk in each frame.

4. A method according to claim 2 wherein the mobile station transmits in timeslots determined by the position of the detected ldenuficaton value for the next two radio blocks if the circuit-switched connection occupies one time slot In the uplmk and downlink only in every alternate frame.

5. A method according to claim 2 wherein the mobile station transmits In tmeslots determined by the position of the detected identification value for the next four radio blocks.

6. A method according to any one of the preceding claims wherem the uplink ordered 11st consists of tlmeslot numbers [NCs+1, ...., Nc5+j]' where NO is the number of the tlmeslot containing the crcuit-swltchcd connection, and Is determined such that NCs+] IS less than or N92215 GBJGL equal to 7, the interval between NCS+1 and NCs IS sufficient to allow the mobile station to perform turnaround to receive with adjacent cell power measurement, and the total number of slots in the unlink ordered list is less than or equal to Tx_max, where Tx_max is the largest of O and the smallest of Sum-3 and Tx-l, where Sam IS the maximum number of slots the mobile can transmit or receive on in a frame and Tx is the maximum number of slots the mobile station can transmit on In a frame.

7. A method according to claim 6 wherem if the crcult-swltched communication link occupies one time slot in the upEnk and downlnk only in every alternate frame, said uplink ordered list further comprises the slot NCs-1 in the final position.

8. A method according to any one of claims 1 to 5 wherem the uplink ordered 11st consist' ' of timeslot numbers [NCS-1, Ncs+l, NCs+2,...., NCs+j]' where NCs IS the number of the timeslot. ..

containing the crcuit-swltched connection, and j is determined such that NCS+1 IS less than or equal to 7, the interval between NCS+1 and NCs IS sufficient to allow the mobile station to perform turnaround to receive with adjacent cell power measurement, and the total number of slots in the uplnk ordered list is less than or equal to Tx_max, where Tx_max is the largest of O and the, , smallest of Snm-3 and Tx-l, where Sum is the maximum number of slots the mobile can transmit.. ë e

or receive on in a frame and Tx IS the maximum number of slots the mobile station can transmit on in a frame.

9. A method according to anyone of claims 1 to 7 wherem the downlmk ordered 11st composes Tx_max tlmeslots from the beginning of the list [NCs-l, NCs-2, ...., Ncs-q], where Tx_maxis the largest of O and the smallest of Sm-3 and Tx-l, where Slim is the maximum number of slots the mobile can transmit or receive on in a frame and Tx is the maximum number of slots the mobile stanon can transmit on in a frame, NCs is the number of the tmeslot containing the crcut-swltched connection, and q IS determined such that Ncs-q IS greater than or equal to O and the interval between Ncs-q and NCs IS sufficient to allow the mobile station to perform turnaround to transmit without adjacent cell power measurement, the tmeslots taken from the list [Ncs-l, NCs-2, ...., Ncs-q] being positioned in ascending order in the downlink ordered list and the download ordered 11st further comprising tmeslot NCs+l.

N92215 GBJGL 17

10. A method according to claim 9 wherein if the crcuit-swltched communication link occupies one time slot in the uplink and downlmk only 1n every alternate frame, said uplink ordered list further comprises the slot NCS in the final position.

11. A method according to any one of claims 1 to 5 or 8 wherem the downlnk ordered list comprises Tx_max timeslots from the beginning of the list [Ncs1, Ncs2, , Ncsq], where Tx_maxis the largest of O and the smallest of Sum-3 and Tx-l, where Am is the maximum number of slots the mobile can transmit or receive on in a frame and Tx is the maximum number of slots the mobile station can transmit on In a frame, NCS is the number of the timeslot containing the crcult-swltched connection, and q is determined such that Ncs-q IS greater than or equal to O and the interval between Ncs-q and NCS is sufficient to allow the mobile station to perform turnaround to transmit without adjacent cell power measurement, the timeslots taken:.'. ' from the list [Ncs1, Ncs2, , Ncs-q] being positioned in ascending order in the downlink. .

ordered list. . . 15, -

12. A method according to claim 11 wherein if the clrcult-swltched communication lank occupies one time slot In the uplmk and downlink only in every alternate frame, said downlmk,, ordered list further comprises the slot NCS in the final position...

13. A method according to any one of the preceding claims wherein said mobile station satisfies the requirements of one of mule-slot classes 6, 7, 10 to 12, 32 to 34 and 37 to 39.

14. A method in a mobile stanon of hransmitung data to a base station over a packet- swltched connection in a ume-dlvlsion multiple access communication system, having a repeating cycle of frames each divided into fimeslots, concurrently with a circuit-switched connection occupying fixed nmeslots In uplink and downlmk channels, the method comprising: consh-ucfing an uplink ordered list of hmeslots and a downlink ordered 11st of umeslots according to a predetermined rule; monutoring fimeslots in the downlink for an idenhficaton value assigned to the mobile stanon to signal the allocation of assigned slots; and when an idenuficanon value assigned to the mobile station IS detected in a tmeslot at position i in said ordered list, hransmitfing on all fimeslots in the uplink ordered list at positions up to and Including i.

N92215 GBJGL 18

15. A method according to claim 14 wherein when the identification value 1S detected, the mobile station ceases to monitor all timeslots in the downlmk ordered 11st at positions before i in the downlink ordered list.

16. A method in a base station for rece1vmg data from a mobile station over a packet- switched connection in a time-dlvlslon multiple access commumcation system, having a repeating cycle of frames each divided into timeslots, concurrently with a arcult-swltched connection occupying fixed timeslots in uplink and downlmk channels, the method comptlsing: constructing an uplink ordered list of timeslots and a downhnk ordered 11st of timeslots according to a predetermined rule; transmitting an identification value in a given timeslot to signal the allocation of assigned slots to said mobile station; and receiving data from the mobile station on all timeslots in the uplmk ordered list at .

positions up to and including i. . 15.

17. A mobile station for transmitting data to a base station over a packet-switched; connection in a tme-dvis1on multiple access communication system, having a repeating cycle of, frames each divided into timeslots concurrently with a circuit-switched connection occupying.

fixed timeslots in uplink and downlink channels, the mobile station comprising: a processor arranged to construct an uplink ordered list of timeslots and a downltnk ordered 11st of timeslots according to a predetermined rule; a receiver arranged to monitor timeslots in the downlink for an identification value assigned to the mobile station to signal the allocation of assigned slots; and a transmitter arrange, when an identification value assigned to the mobile station is detected in a timeslots at position i In said ordered list, to transmit on all timeslots in the uplink ordered 11st at positions up to and including'.

18. A mobile station according to claim 17 wherein said receiver is further adapted, when the identification value IS detected, to cease to momtor all timeslots in the downlink ordered list at positions before i In the downlink ordered list.

19. A base station for receiving data from a mobile station over a packetswitched connection in a tme-divis1on multiple access communication system, having a repeating cycle of N92215 GBJGL 19 frames each divided into tmeslots, concurrently with a circuit-switched connection occupying fixed timeslots in uplink and downlmk channels, the base station compnsmg: a processor arranged to construct an uplink ordered list of timeslots and a downlnk ordered list of timeslots according to a predetermined rule; a transmitter arranged to transmit an identification value m a given timeslot to signal the allocation of assigned slots to said mobile station; and a receiver arranged to receive data from the mobile station on all tmeslots in the uplmk ordered list at positions up to and 1ncludmg i. _ f

20. A communication system comprising a base station according to claims 16 and a mobile station according to claim 17 or 18.

21. A computer program compnsmg program code means that, when executed by a .

processor In a mobile station instructs the mobile station to effect the method of claim 14 or 15 . 15:..,:.

22. A computer program comprising program code means that, when executed by a processor in a base station, instructs the base station to effect the method of claim 16. :-