U.S. patent application number 10/814784 was filed with the patent office on 2005-06-23 for dynamic resource allocation in packet data transfer.
This patent application is currently assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.. Invention is credited to Cooper, David Edward.
Application Number | 20050135327 10/814784 |
Document ID | / |
Family ID | 9956020 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050135327 |
Kind Code |
A1 |
Cooper, David Edward |
June 23, 2005 |
Dynamic resource allocation in packet data transfer
Abstract
A method for control of packet data transmissions in a TDMA
wireless network to provide for additional choices in the
allocation of communication channels. Measurement and recovery
periods are re-assigned to avoid conflicts in operating conditions.
The re-assignments for the GPRS system may be reduced to a simple
formula.
Inventors: |
Cooper, David Edward;
(Newbury, GB) |
Correspondence
Address: |
STEVENS DAVIS MILLER & MOSHER, LLP
1615 L STREET, NW
SUITE 850
WASHINGTON
DC
20036
US
|
Assignee: |
MATSUSHITA ELECTRIC INDUSTRIAL CO.,
LTD.
Osaka
JP
|
Family ID: |
9956020 |
Appl. No.: |
10/814784 |
Filed: |
April 1, 2004 |
Current U.S.
Class: |
370/347 |
Current CPC
Class: |
H04W 72/044 20130101;
H04W 24/10 20130101 |
Class at
Publication: |
370/347 |
International
Class: |
H04Q 007/24 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 2, 2003 |
GB |
0307585.0 |
Claims
What is claimed is:
1. A method for controlling packet data transmissions in a mobile
communications system wherein transmitters and receivers share
channel resources dynamically for uplink and downlink operating
periods and where allocations of measurement periods between uplink
and downlink periods and between downlink and uplink periods are
prescribed, characterised by re-allocation of measurement periods
to increase the availability of uplink resources when uplink
resources are otherwise constrained by prescribed allocations of
measurement periods.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to multiple access communication
systems and in particular it relates to dynamic resource allocation
in time division multiple access systems.
[0003] 2. Description of Related Art
[0004] In Multiple access wireless systems such as GSM, a number of
mobile stations communicate with a network. The allocation of
physical communication channels for use by the mobile stations is
fixed. A description of the GSM system may be found in The GSM
System for Mobile Communications by M. Mouly and M. B. Pautet,
published 1992 with the ISBN reference 2-9507190-0-7.
[0005] With the advent of packet data communications over Time
Division Multiple Access (TDMA) systems, more flexibility is
required in the allocation of resources and in particular in the
use of physical communication channels. For packet data
transmissions in General Packet Radio Systems (GPRS) a number of
Packet Data CHannels (PDCH) provide the physical communication
links. The time division is by frames of 4.615 ms duration and each
frame has eight consecutive 0.577 ms slots. A description of the
GPRS system may be found in (GSM 03.64 V 8.5 release 1999). The
slots may be used for uplink or downlink communication. Uplink
communication is a transmission from the mobile station for
reception by the network to which it is attached. Reception by the
mobile station of a transmission from the network is described as
downlink.
[0006] In order to utilise most effectively the available
bandwidth, access to channels can be allocated in response to
changes in channel conditions, traffic loading Quality of Service
and subscription class. Owing to the continually changing channel
conditions and traffic loadings a method for dynamic allocation of
the available channels is available.
[0007] The amounts of time that the mobile station receives
downlink or transmits uplink may be varied and slots allocated
accordingly. The sequences of slots allocated for reception and
transmission, the so-called multislot pattern is usually described
in the form RXTY. The allocated receive (R) slots being the number
X and the allocated transmit slots (T) the number Y.
[0008] A number of multislot classes, one through to 29, is defined
for GPRS operation and the maximum uplink (Tx) and downlink (Rx)
slot allocations are specified for each class. The specification
for multislot class 12 is shown in Table 1 below.
[0009] In a GPRS system, access to a shared channel is controlled
by means of an Uplink Status Flag (USF) transmitted on the downlink
to each communicating mobile station (MS). In GPRS two allocation
methods are defined, which differ in the convention about which
uplink slots are made available on receipt of a USF. The present
invention relates to a particular allocation method, in which an
equal number "N" of PDCH's, where a "PDCH" uses a pair of uplink
and downlink slots corresponding to each other on a 1-1 basis, are
allocated for potential use by the MS. The uplink slots available
for actual use by a particular mobile station sharing the uplink
channel are indicated in the USF. The USF is a data item capable of
taking 8 values VO-V7, and allows uplink resources to be allocated
amongst up to 8 mobiles where each mobile recognises one of these 8
values as "valid", i.e. conferring exclusive use of resources to
that mobile. In the case of the extended dynamic allocation method,
for example, reception of a valid USF in the slot 2 of the present
frame will indicate the actual availability for transmission of
transmit slots 2 . . . N in the next TDMA frame or group of frames,
where N is the number of allocated PDCHs. Generally for a valid USF
received at receiver slot n, transmission takes place in the next
transmit frame at transmit slots n, n+1 et seq. to the allocated
number of slots (N). For the extended dynamic allocation method as
presently defined these allocated slots are always consecutive.
[0010] The mobile station is not able instantly to switch from a
receive condition to a transmit condition or vice versa and the
time allocated to these reconfigurations is known as turnaround
time. The turnaround time is a concept including both a time
required for switching from a receive condition to a transmit
condition, that is, a time required for getting ready to transmit,
and a time required for switching from a transmit condition to a
receive condition, that is, a time required for getting ready to
receive. As presently defined the turnaround time depends upon the
class of mobile. A turnaround time of one slot is allocated in the
case of class 12 mobiles such as are used for the exemplary
embodiment described later. It is also necessary for the mobile
station, whilst in packet transfer mode, to perform adjacent cell
signal level measurements. The mobile station has continuously to
monitor all Broadcast Control Channel (BCCH) carriers as indicated
by the BA(GPRS) list and the BCCH carrier of the serving cell. A
received signal level measurement sample is taken in every TDMA
frame, on at least one of the BCCH carriers. (3GPP TS 05.08
10.1.1.2) .
[0011] These adjacent cell signal level measurements are taken
prior to re-configuration from reception to transmission or prior
to re-configuration from transmission to reception. The number of
slots allocated to each combination of these adjacent cell signal
level measurements and re-configurations (turnaround) for multislot
class 12 is two. As the combination of adjacent cell signal level
measurement and turnaround, it is noted that there are 4 patterns
of combinations as described later, including the (2 patterns of)
combinations of adjacent cell signal level measurement and
turnaround (getting ready to transmit or getting ready to receive:
hereafter referred to as "transmit/receive preparation" in
abbreviated terms) and (another 2 patterns of) turnaround
(transmit/receive preparation) only. Hereafter, these combinations
are abbreviated as "turnaround (and adjacent cell signal level
measurement)."
[0012] Arising from the requirement to allocate particular slots
for turnaround (and adjacent cell signal level measurement)
purposes, some restrictions occur and potential dynamic channel
allocations are lost. These restrictions reduce the availability of
slots for uplink transmissions; reduce the flow of data and reduce
the flexibility of response to changing conditions.
[0013] An exhaustive technical review and wholesale change to the
existing prescribed operating conditions might be expected to
alleviate the problems associated with dynamic allocation. Whilst
this is possible, the considerable difficulties caused by such
wholesale change would be generally unwelcome and this resolution
of the technical problem is unlikely.
[0014] There is a need therefore to provide a solution to the
problems affecting dynamic channel allocation with minimal effect
on existing prior art methods.
SUMMARY OF THE INVENTION
[0015] It is an object of this invention to reduce the restrictions
affecting dynamic channel allocation with minimal effect on the
existing prescript.
[0016] In accordance with the invention there is provided a method
for controlling packet data transmissions as set out in the
attached claims.
[0017] In the case of the present invention, more transmission
capacity has been enabled by allowing some transmission patterns
that otherwise would not comply with the specified rules while
maintaining the conventional use of GSM timing advance and slot
allocation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 illustrates the GPRS TDMA frame structure showing the
numbering convention used for uplink and downlink slots;
[0019] FIG. 2 illustrates a 3 slot allocation and a state
transition from R3T0 to R3T2;
[0020] FIGS. 3 to 5 show 2 PDCH extended dynamic allocations in
steady state for R2T0, R2T1 and R2T2 respectively with associated
adjacent cell signal level measurement and turnaround
intervals;
[0021] FIG. 6 is a state transition diagram for 2 PDCH extended
dynamic allocations;
[0022] FIGS. 7 to 11 show the state transitions of FIG. 6;
[0023] FIG. 12 to 15 show the 3 PDCH extended dynamic allocation in
steady state;
[0024] FIG. 16 is a state transition diagram for 3 PDCH extended
dynamic allocation;
[0025] FIGS. 17 to 25 show the state transitions of FIG. 16;
[0026] FIGS. 26 to 30 show the steady state 4 slot extended dynamic
allocation of the prior art;
[0027] FIGS. 31 to 35 show the steady state 4 slot extended dynamic
allocation in accordance with the invention;
[0028] FIG. 36 is a state transition diagram for 4 slot extended
dynamic allocation in accordance with the invention;
[0029] FIGS. 37 to 50 show the state transitions of FIG. 36;
[0030] FIG. 51 is an exemplary block diagram for illustrating one
example of a mobile station which is adaptable to the present
embodiment;
[0031] FIG. 52 is a flowchart for illustrating an operation example
of the slot allocation calculator 128 in FIG. 51; and
[0032] FIG. 53 is an exemplary block diagram for illustrating one
example of a base station which is adaptable to the present
embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] In this embodiment, the invention is applied to a GPRS
wireless network operating in accordance with the standards
applicable to multislot class 12 in extended dynamic
allocation.
[0034] In FIG. 1 the GPRS TDMA frame structure is illustrated and
shows the numbering convention used for uplink and downlink slots.
It should be noted that in practice Tx may be advanced relative to
Rx due to timing advance in accordance with conventional GSM usage,
although this is not shown in the illustration. Thus in practice
the amount of time between the first Rx and first Tx of a frame may
be reduced by a fraction of a slot from the illustrated value of 3
slots due to timing advance.
[0035] FIG. 1 illustrates two successive TDMA frames with receiver
(Rx) and transmitter (Tx) slots identified separately. The slot
positions within the first frame are shown by the numerals 1
through to 8 with the transmission and reception slots offset by a
margin of three slots. This is in accordance with the convention
that that the first transmit frame in a TDMA lags the first receive
frame by an offset of 3 (thus ordinary single slot GSM can be
regarded as a particular case in which only slot 1 of transmit and
receive is used).
[0036] The remaining figures (save for the state transition
diagrams and block diagrams) conform to the illustration of FIG. 1
but the slot numbering has been removed for extra clarity. The
shaded slots are those allocated for the particular states, and the
arrowed inserts, e.g. numerals 41 and 42 of FIG. 4, indicate the
applicable turnaround (and adjacent cell signal level measurement)
intervals and number of slots allocated for these intervals. The
hashed slots, e.g. numeral 43 of FIG. 4, indicate reception of a
valid USF. As mentioned above, constraints are imposed by the need
to allow slots for turnaround (and adjacent cell signal level
measurement), and the prescript for these in 3GPP TS 05.02 Annex B
limits dynamic allocation as shown in table 1 for the example of
multislot class 12.
1TABLE 1 Multislot Maximum number of slots Minimum number of slots
class Rx Tx Sum T.sub.ta T.sub.tb T.sub.ra T.sub.rb 12 4 4 5 2 1 2
1
[0037] T.sub.ta is the time needed for the MS to perform adjacent
cell signal level measurement and get ready to transmit
[0038] T.sub.tb is the time needed for the MS to get ready to
transmit
[0039] T.sub.ra is the time needed for the MS to perform adjacent
cell signal level measurement and get ready to receive
[0040] T.sub.rb is the time needed for the MS to get ready to
receive
[0041] It should be noted that in practice the times T.sub.ta and
T.sub.tb may be reduced by a fraction of a slot due to timing
advance.
[0042] A period for extended dynamic allocation including adjacent
cell signal level measurement is specified as T.sub.ra (3GPP TS
05.02 6.4.2.2). That is to say that all adjacent cell signal level
measurements are taken just before the first receive slot and not
before the transmit slot.
[0043] If there are m slots allocated for reception and n slots
allocated for transmission, then there must be Min(m,n) reception
and transmission slots with the same slot number.
[0044] Here, an explanation is given on the extended dynamic
allocation method that is the technique on which the present
invention is predicated. According to the extended dynamic
allocation method, a pair of a receive frame and a transmit frame
corresponds to each other on a 1-1 basis with a predetermined
offset, where transmission is started from a transmit slot having
the same number as that of a receive slot in which a valid USF was
received. The starting of transmission is done from the next
transmission frame of the transmission frame corresponding to the
reception frame in which a valid USF is received. The number of
transmit slots for transmission in a transmit frame equals to the
slot numbers allocated to the transmit frame (N), and slots to be
transmitted in a transmit frame are always consecutive. The
starting position of transmit slots is maintained until the
reception of the next valid USF.
[0045] For example, with reference to FIG. 2, an example of a 3
slot allocation, annotated R3T0.fwdarw.R3T2, is shown with no
uplink slot allocated initially. A valid USF 21 received on Rx slot
2 allows 2 TX slots on the next uplink frame. The annotation
".fwdarw." indicates a change of state. Here, as described above,
R3T0 indicates receive slots of 3 and transmit slots of 0, while
R3T2 indicates receive slots of 3 and transmit slots of 2. In this
case, because a valid USF 21 has been received on Rx slot 2 in the
R3T0 state, the starting position of transmit slots in the next
transmission frame (the R3T2 state after transition) is Tx slot 2.
At this time, the number of transmit slots to be transmitted is 2,
which is the same as the number of the allocated transmitted slots,
and these two transmit slots are consecutive.
[0046] FIGS. 3 to 5 show steady state extended dynamic allocations
for 2 PDCH according to the annotations and the turnaround (and
adjacent cell signal level measurement) intervals are marked. For
example, in the case of FIG. 3 allocation, consecutive two frames
are in the same state because they are in a steady state. R2T0
indicates that the number of receive slots is 2 and the number of
transmit slots is 0. In this case, T.sub.tb is unnecessary because
there is no transmission. T.sub.ra starts at two slots before the
reception of the next frame.
[0047] FIG. 4 illustrates steady state extended dynamic allocation
for R2T1 (Rx 2 slots, Tx 1 slot). In this case, a valid USF 43
received on Rx slot 2 allows one Tx slot on the next uplink frame.
At this time, the starting position of the allowed transmit slot is
Tx slot 2, which has the same slot number as the reception position
of the valid USF 43 (Rx slot 2) in accordance with the extended
dynamic allocation described above.
[0048] FIG. 6 is a state transition diagram for 2 PDCH extended
dynamic allocations and shows all of the allowed states.
Specifically, as illustrated in FIG. 6, an aggregate of five state
transitions are allowed, including, from R2T0 (Rx 2 slots, Tx 0
slot) to R2T1 (Rx 2 slots, Tx 1 slot), from R2T0 to R2T2 (Rx 2
slots, Tx 2 slots), from R2T1 to R2T0, from R2T1 to R2T2, and from
R2T2 to R2T0.
[0049] FIGS. 7 through to 11 show the slot positions and applicable
turnaround (and adjacent cell signal level measurement) intervals
for the transitions of FIG. 6.
[0050] For example, FIG. 7 illustrates a state transition from R2T1
to R2T2. In this case, because a valid USF 71 has been received on
Rx slot 1 in the R2T1 state, the starting position of transmit
slots in the next transmission frame is Tx slot 1.
[0051] Steady state 3 PDCH extended dynamic allocations are shown
in FIGS. 12 to 15. The state transitions for 3PDCH are shown in
FIG. 16 and the corresponding slot positions and turnaround (and
adjacent cell signal level measurement) intervals in FIGS. 17 to
25. It can be seen that for all of the illustrations no impediment
to slot allocation arises from the application of the turnaround
(and adjacent cell signal level measurement) intervals.
[0052] With 4 slot extended dynamic allocations, however conflicts
occur and the prescribed conditions do not permit implementation
beyond the steady state R4T0 case illustrated in FIG. 26. This is
because the constraint T.sub.ra=.sup.2 for accommodating adjacent
cell signal level measurement cannot be applied since Tx slot 4 is
always used, leaving only a single slot turnaround (receive
preparation) time before Rx slot 1. Examples of allowed and
prohibited 4 slot extended dynamic allocations in accordance with
the prior art are shown in FIGS. 26 to 30. These indicate steady
states and the four receive slots and no transmit slot R4T0 state
of FIG. 26 is allowed. The allocations prohibited are overlaid by a
"no entry" logo (e.g. numeral 301 of FIG. 30) in the illustrations
of FIG. 27, R4T1, FIG. 28, R3T2, FIG. 29 R2T3 and FIG. 30 R1T4. It
can be seen that these prohibitions arise because of the limitation
of just one slot allowed for time T.sub.ra for adjacent cell signal
level measurement and transmit preparation (the time needed to
perform adjacent cell signal level measurement and then prepare for
transmission).
[0053] In accordance with the invention, periods for adjacent cell
signal level measurement and turnaround (transmit/receive
preparation) are re-allocated to increase the availability of
uplink resources when the uplink resources are otherwise
constrained by prescribed allocations.
[0054] Application of the method in accordance with the invention
provides for the previously prohibited allocations of FIGS. 27 to
30 to be admitted as shown in FIGS. 32 to 35. If N slots are
allocated, and N+T.sub.ra+3.ltoreq.8 (number of slots in a frame),
then T.sub.ra is used as the interval accommodating adjacent cell
signal level measurement, otherwise if N+T.sub.ra+3>8 (condition
XX), then T.sub.ta is used as the interval accommodating adjacent
cell signal level measurement;
[0055] where
[0056] .ltoreq.less than or equal to
[0057] >greater than
[0058] T.sub.ta is the time needed to perform adjacent cell signal
level measurement and then prepare for transmission.
[0059] Application of the method to the steady state R4T1 is shown
in FIG. 32.
[0060] With the number of PDCH's allocated N=4, the adjacent cell
signal level measurement and turnaround interval T.sub.ra=2,
N+T.sub.ra+3>8 (4+2+3=9) and therefore T.sub.ta is used as the
interval accommodating adjacent cell signal level measurement. The
impediment to operation shown in FIG. 27 is therefore removed by
application of the method as illustrated in FIG. 32.
[0061] This procedure is implemented in the mobile station which
when using the extended dynamic allocation method, and on receiving
an allocation of PDCH numbering "N", must perform the comparison
above in order to time the radio link measurement procedure
correctly.
[0062] The procedure performed by the network equipment is that
when allocating a number of PDCHs "N", it recognises that when N
satisfies the condition (XX) above it must take into account the
capability of the mobile station to perform adjacent cell signal
level measurements using T.sub.ta and provided that:
[0063] N+T.sub.rb+3.ltoreq.8, is capable of allocating such a
number of PDCHs.
[0064] The method may be applied successfully to the remaining
steady states shown in FIGS. 33, 34 and 35. Furthermore the method
is effective for all of the 4 slot state transitions shown in the
state transition diagram FIG. 6. Illustrations of the 4 slot state
transitions are given in FIGS. 37 through to 50.
[0065] FIG. 51 is a block diagram for a mobile station (MS) which
is adaptable to the present embodiment.
[0066] A mobile station (wireless data communication terminal) 100
allows the bi-directional transfer of data between a base station
200 and an external data source and sink 130.
[0067] Downlink
[0068] The base station 200 transmits GPRS signals to the mobile
station 100. The GPRS signals are received on the receive antenna
102, and are demodulated to baseband ones by a radio frequency
demodulator 108. The radio frequency demodulator 108 delivers the
baseband signals to a baseband data receiver 106. The baseband data
receiver 106 delivers the received baseband data to a demultiplexer
110. The demultiplexer 110 selects either an NCELL measurement unit
112 or a Layer 2 protocol unit 114 to process the above data,
depending on its control input from a timing controller 120.
[0069] If the downlink baseband data is destined for the NCELL
measurement unit 112, this unit performs adjacent cell signal level
measurement, and transmits the resulting information to a Layer 3
protocol unit 116. The Layer 3 protocol unit 116 in turn transmits
the data to the base station 200 via the uplink.
[0070] Downlink baseband data to be used for adjacent cell signal
level measurement is routed to the Layer 3 protocol unit 116. The
Layer 3 protocol unit 116 separates user plane data and control
plane data. The user data is sent to a terminal interface unit 118.
The terminal interface unit 118 sends the data to an external data
source and sink 130.
[0071] Control
[0072] Control plane data is used to perform internal control
functions. In particular, any GPRS slot allocation frames sent from
the base station 200 are used to send parameter data to a slot
allocation calculator 128. The slot allocation calculator 128
calculates which TDMA slots shall be used for data reception, data
transmission, and adjacent cell signal level measurement purposes.
This information is sent to a timing controller setting calculator
126. The timing controller setting calculator 126 in turn
reconfigures a timing controller 120 so as to perform each
operation of receive preparation, transmit preparation, and
adjacent cell signal level measurement at the correct time.
[0073] FIG. 52 is a flowchart illustrating an operation example of
the slot allocation calculator 128.
[0074] First, in step S1000, parameter Tra_flag is set into 1,
while parameters Tr and Tt are set to values of Tra[class] and
Ttb[class] respectively. Herein, Tra_flag is a parameter indicating
which one of T.sub.ra and T.sub.ta should be used as the interval
accommodating adjacent cell signal level measurement, where the
parameter indicates that T.sub.ra should be used when set to 1, and
that T.sub.ta should be used when set to 0. Tra[class] and
Ttb[class] are values of T.sub.ra and Ttb allocated to class
(multislot class of a mobile station), which is an input parameter,
respectively. The number of the class is a property of the mobile
station. In addition, the value of T.sub.ra, T.sub.tb corresponding
to each class is pre-stored in the format of, for example, Table
1.
[0075] Then, at step S1100, parameter Rxmin is set to the value of
Tr as set in step S1000. Here, Rxmin is a parameter indicating the
number of the first slot in downlink receive slots.
[0076] Then, at step S1200, the number of transmit slots (Tx) and
the number of receive slots (Rx) is compared with each other. As
the result of the comparison, if Tx.gtoreq.Rx (S1200: NO), the
process goes to step S1300, whereas if Tx<Rx (S1200: YES), it
moves on to step S1500. It is noted that each value of Tx, Rx is
included in the radio resource control plane data from the upper
layer.
[0077] At step S1300, it is further judged whether Rx+Tt is less
than 3 or not. Here, "3" is the number of slots for downlink and
uplink offset. As the result of the judgment, if Rx+Tt<3 (S1300:
YES), the process goes to step S1400, whereas if Rx+Tt.gtoreq.3
(S1300: NO), it moves on to step S1500.
[0078] At step S1400, parameter Txmin is set to Tr+3. Meanwhile, at
step S1500, parameter Txmin is set to Tr+Rx+3. Here, Txmin is a
parameter indicating the number of the first slot in uplink
transmit slots. Incidentally, the value set in step S1000 is used
for Tr.
[0079] Then, at step S1600, parameter Txmax is set to Txmin+Tx.
Here, Txmax is a parameter indicating the number of the next slot
of the last slot in uplink transmit slots. Incidentally, the value
set in step S1400 or step S1500 is used for Txmin.
[0080] Then, in step S1700, it is judged whether to end processing
or not. Specifically, it is judged whether the processing from step
S1100 through step S1600 is the first execution or the second
execution. As the result of the judgment, if the processing is not
ended, that is, if the processing from step S1100 through step
S1600 is the first execution (S1700: NO), the process goes to step
S1800, whereas if the processing from step S1100 through step S1600
is the second execution (S1700: YES), a string of processing is
ended.
[0081] At step S1800, it is judged whether Txmax set in step S1600
is less than 8 or not. Here, "8" is the number of slots contained
in one frame. As the result of the judgment, if Txmax.ltoreq.8
(S1800: YES), the string of processing is ended, whereas if
Txmax>8 (S1800: NO), the process goes to step S1900.
[0082] In step S1900, parameter Tra_flag is set into 0, while
parameters Tr and Tt are set to values of Trb[class] and Tta[class]
respectively, and after that, the process goes to step S1100 to
repeat processing from step S1100 through step S1600. Herein,
Trb[class] and Tta[class] are values of T.sub.rb and T.sub.ta
allocated to class, which is an input parameter, respectively. As
described above, the number of class is included in the radio
resource control plane data from the upper layer, and in addition,
the value of T.sub.rb, T.sub.ta corresponding to each class is
pre-stored in the format of Table 1. Incidentally, upon completion
of the processing from step S1100 through step S1600 (S1700: YES),
the string of processing is ended.
[0083] Upon the completion of the string of processing as the
result of the judgment in step S1800 (S1800: YES) or as the result
of the judgment in step S1700 (S1700: YES), each value of
parameters at the time of the end, Tra_flag, Rxmin, Txmin, and
Txmax, is outputted as information.
[0084] In short, first, it is checked whether it is possible to use
T.sub.ra as a period accommodating adjacent cell signal level
measurement, that is, whether it is possible to use T.sub.ra and
T.sub.tb as a combination of intervals. Specifically, if the number
of downlink receive slots (Rx) is greater than the number of uplink
transmit slots (Tx) (S1200: YES), and if Rx+Tt is equal to or
greater than 3 (S1300: NO), Txmin is set to Tr+Rx+Tt (S1500), and
otherwise, Txmin is set to Tr+3 (S1400). Then, Txmax is set to
Txmin+Tx (S1600). Then, if Txmax is equal to or less than 8 (S1800:
YES), T.sub.ra is used as a period accommodating adjacent cell
signal level measurement, that is, T.sub.ra and T.sub.tb is used as
a combination of intervals. Contrarily, if Txmax exceeds 8 (S1800:
NO), T.sub.ta is used as a period accommodating adjacent cell
signal level measurement, that is, T.sub.rb and T.sub.ta is used as
a combination of intervals.
[0085] It is noted that, though the operation example in FIG. 52
assumes the processing in step S1100 through step S1600 to be
reexecuted once again after step S1900, the invention is not
limited to such a case. If any parameters other than Tra_flag (for
example, Rxmin, Txmin, Txmax, etc.) are unnecessary as output, that
is, if it is just enough to set Tra_flag only, the processing may
be ended immediately without repeating any processing from step
S1100 through step S1600 after step S1900.
[0086] The timing controller 120 is responsible for determining and
controlling the timing of the transmission and reception of signals
toward the base station 200, and the reception of measurement data.
In accordance with the calculation result of the slot allocation
calculator 128, the timing controller 120 controls the precise
timing and behaviour of the radio frequency modulator 122, radio
frequency demodulator 108, baseband data receiver 106, baseband
transmitter 124, and demultiplexer 110. Specifically, it controls
each section in such a manner that, if Tra_flag=1, T.sub.ra is used
as a period accommodating adjacent cell signal level measurement,
whereas if Tra_flag=0, T.sub.ta is used as a period accommodating
adjacent cell signal level measurement.
[0087] Uplink
[0088] User data transmitted from an external data source and sink
130 is accepted by a terminal interface unit 118, and given to a
Layer 3 protocol unit 116. The Layer 3 protocol unit 116
multiplexes the data with any protocol control data, and transmits
it via a Layer 2 protocol unit 114. The Layer 2 protocol unit 114
in turn transmits the multiplexed data to a baseband transmitter
124. Subsequently, the multiplexed data is modulated by a radio
frequency modulator 122, and then is transmitted over a transmit
antenna 104.
[0089] FIG. 53 is a block diagram for a base station which is
adaptable to the present embodiment.
[0090] A wireless base station 200 allows the bi-directional
transfer of data between a plurality of mobile stations 100 and an
external base station controller (BSC: Base Station Controller)
230.
[0091] Up link
[0092] Each mobile station 100 transmits precisely-timed GPRS
signals to the base station 200. The GPRS signals are received on
the receive antenna 202, and are demodulated to baseband ones by a
radio frequency demodulator 208. The radio frequency demodulator
208 delivers the baseband signals to a baseband data receiver 206.
If multiple receive frequencies are used, there is one set of radio
frequency demodulator 208 and baseband data receiver 206 per
frequency. The baseband data receiver 206 delivers the received
baseband data to a multiplexer MS 210. The multiplexer MS 210 marks
which MS the data has arrived from depending on its control input
from a timing controller 220, and forwards all data to a Layer 2
protocol unit 214. The Layer 2 protocol unit 214 maintains a
separate context for each mobile station 100.
[0093] Downlink baseband data to be used for NCELL measurement is
routed to a Layer 3 protocol unit 216. The Layer 3 protocol unit
216 maintains a separate context for each mobile station 100. The
Layer 3 protocol unit 216 separates user plane data and radio
resource control plane data. User data and radio resource control
plane data is sent to a BSC interface unit 218. The BSC interface
unit 218 sends the data to an external base station controller
230.
[0094] Control
[0095] Radio resource control plane data is used to perform
internal control functions. In particular, a slot allocation
calculator 228 calculates, typically according to the data rate
required, which GPRS slots are allocated for each mobile station
100. This information is sent to the Layer 3 protocol unit 216. The
Layer 3 protocol unit 216 sends allocation information to the
mobile station 100. This information is also sent to a timing
controller setting calculator 226. In addition, other MS slot
allocator 232 receives necessary data from the external Base
station controller 230 via the BSC interface unit 218, and
calculates allocation information for other mobile stations. This
information is also sent to the timing controller setting
calculator 226. The timing controller setting calculator 226 in
turn reconfigures a timing controller 220 so as to perform each of
receive and transmit actions towards each mobile station 100 at the
correct time.
[0096] The timing controller 220 is responsible for determining and
controlling the timing of the transmission and reception of signals
toward the mobile station 100. In accordance with the calculation
result of the slot allocation calculator 228, the timing controller
220 controls the precise timing and behaviour of the radio
frequency modulator 222, radio frequency demodulator 208, baseband
data receiver 206, baseband transmitter 224, multiplexer MS 210,
and demultiplexer MS 234.
[0097] Downlink
[0098] User data and control data transmitted from a base station
controller 230 is accepted by a BSC interface unit 218, and given
to a Layer 3 protocol unit 216. The Layer 3 protocol unit 216
multiplexes the data with any radio resource control data, and
transmits it via a Layer 2 protocol unit 214. The Layer 2 protocol
unit 214 in turn transmits the multiplexed data to a demultiplexer
MS 234. The demultiplexer MS 234 provides the data for each mobile
station 100 on the correct TDMA slot to the correct baseband
transmitter 224. Subsequently, the data is modulated by a radio
frequency modulator 222, and then is transmitted over a transmit
antenna 204. If multiple transmit frequencies are used, there is
one set of radio frequency modulator 222 and baseband data
transmitter 224 per frequency.
* * * * *