Method and system for determining time and frequency resources.

METHOD AND SYSTEM TO DETERMINE TIME RESOURCES AND

FREQUENCY

FIELD OF THE INVENTION

The present invention generally relates to the determination and signaling of time and frequency resources that are to be used to carry out transmissions within a wireless communication network.

BACKGROUND OF THE INVENTION

In order to perform transmissions within a wireless communication network, wireless communication network resources need to be allocated by a wireless communication network device in charge of coordinating resource usage. Resource allocations need to be signaled within the wireless communications network so that each device in the wireless communications network is aware of which resources have to be used effectively to make such transmissions.

Time and frequency resources are typically used to allow the execution of such transmissions. Time is divided into equal-sized time slots, which then defines the time resources. Multiple frequencies or frequency bands are

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available to perform the _{: n: c&gt;} in ... ri] al then defines the frequency resources. The use of said frequency or frequency band during a time slot defines a time and frequency resource. Time and frequency resources are typically represented using a grid, with frequency resources on one axis and time resources on another axis. When considering, for example, a set of sixteen frequency bands over twenty time slots, the signaling information typically consists of eighty bits, four bits to cover the sixteen frequency resources for each of the twenty time resources. Said figures consider the case where one and only one frequency resource is assigned per time slot for said transmissions. More signaling bits may be required to indicate whether one or the other time slot is left free.

BRIEF DESCRIPTION OF THE INVENTION

It is known in the art that reducing an amount of information exchanged within a wireless communication network is a key goal in properly managing the use of wireless communication network resources. The present invention focuses on providing a solution that allows to reduce the signaling information

<img file="MX358486B_D0002.tif" />

provided to determine which time-frequency resources are used within the wireless communications network to make transmissions, while a certain level of frequency diversity is guaranteed to improve the probability of success of said transmissions.

To that end, the present invention relates to a method for determining time and frequency resources among time and frequency resources of a wireless communication network that is going to be used to carry out transmissions in said wireless communication network, the transmissions being performed over time and frequency resources of the wireless communication network according to an initial grid representation. The method is such that a first device in charge of allocating time and frequency resources performs the following: obtaining groups of time and frequency resources from the wireless communication network to form a grid representation that was redrawn; allocating time and frequency resources according to the redrawn grid representation and according to a frequency hopping criterion; provide signaling information representative of time and frequency resources that have been allocated according to the grid representation that was re-mapped

IMPI

MIWICANC INSTITUTE OE INDUSTRIAL PROPERTY trace. The method is also such that, to determine the time and frequency resources of the initial grid representation are going to be used to carry out said transmissions, a second device does the following: obtain the signaling information provided by the first device to determine the time and frequency resources that have been allocated according to the grid representation that was redrawn; and applying a predetermined pattern mask over the determined time and frequency resources that have been allocated according to the redrawn grid representation, the pattern mask being such that only a time and frequency resource of the initial grid it is effectively allocated per timeslot on each allocated time and frequency resource of the redrawn grid.

Therefore, adaptive allocation of time and frequency resources can be achieved with limited signaling overhead.

According to a particular characteristic, the first device defines the groups of time and frequency resources by selecting a grid representation that was redrawn from among a first plurality of predefined redrawn grid representations, the first device indicates, on the

INSTITUTO MEXICANO faá'-A, i DE l&gt; INDUSTRIAL PROPERTY signaling information, which representation of re j i'TTT ^ **** · that was redrawn has been selected, and the second device determines, from the signaling information, which grid representation that was redrawn has been selected.

Therefore, more flexibility is provided in the allocation of time and frequency resources through various possibilities of redrawn grids and performance can be improved.

According to a particular characteristic, the first device selects the grid that was redrawn through the following: calculating, for each grid that was redrawn of said first plurality, a first figure of merit representative of the robustness for the interference for the selected redrawn grid; and selecting the grid that was redrawn from said first plurality showing the best first figure of merit.

Therefore, the redrawn grating is selected so that the robustness for interference can be improved and performance is improved.

According to a particular characteristic, the first device selects a pattern mask from a second plurality of predefined pattern masks, the first device indicates in the

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<img file="MX358486B_D0004.tif" />

signaling information which pattern mask has been selected, and the second device applies said selected pattern mask to determine which initial grid time and frequency resources are to be used to perform said transmissions.

Therefore, more flexibility is provided in the allocation of time and frequency resources through various possibilities of pattern masks and performance can be improved.

According to a particular characteristic, the first device selects the pattern mask through the following: calculating, for each pattern mask of said second plurality, a second figure of merit representative of the robustness for interference for said pattern mask ; and selecting the pattern mask of said second plurality displaying the best second figure of merit.

Therefore, the pattern mask is selected in order to improve the robustness for interference and the performance is improved.

According to a particular characteristic, the first device selects a pattern mask from among a second plurality of predefined pattern masks, the first device indicates in the signaling information which pattern mask has been

IMPI

<img file="MX358486B_D0005.tif" />

MEXICAN INSTITUTE '&gt;

Say LA PRFFIEDA »INDUSTRIAL selected, and the second device applies said selected pattern mask to determine which resources &lt;Je time and frequency of the initial grid are going to be used to carry out said transmissions. The first device selects the redrawn grid and mask pattern by: calculating, for each redrawn grid pair of said first plurality and pattern mask of said second plurality, a third figure of merit representative of the robustness to interference for said redrawn grating and pattern mask pair; and select the grid pair to be redrawn and pattern mask showing the best third figure of merit.

Therefore, more flexibility is provided in the allocation of time and frequency resources through various possibilities of redrawn grids and pattern masks and performance can be improved according to optimization of the figure of merit.

According to a particular characteristic, the pattern masks of said second plurality have the same level of orthogonality to each other.

Therefore, when different pattern masks are selected for different systems, those different systems interfere with each other in the same way and

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INSTITirro MIXICANC. 'Ff'if — C. M THE PROPERTY

INDUSTRIAL there is no need for joint optimization. In other words, a cooperation between said different systems is not required.

According to a particular characteristic, for each time slot of the initial grid, the groups of the redrawn grid are formed by grouping adjacent frequencies or frequency bands of the initial grid into super-frequency bands.

Therefore, when the interferences have a bandwidth greater than the bandwidth of the system used for transmission, avoiding the interference of these interference factors is obtained with a limited signaling overhead.

According to a particular characteristic, an orthogonality factor OF is defined between pairs of sequences of time and frequency resources within respective super-frequency bands on said v consecutive time slots, as follows:

OF (I1,12) = W (f (Il; l) -f (I2; l)) + W (f (I2; l) -f (Il; l)) + ...

+ W (f (Il; v) -f (I2; v)) + W (f (I2; v) -f (Il; v)) where II and 12 are sequences of time and frequency resources defined by two respective pattern masks within an identically formed super-frequency band over a number of v

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OF THE FFOPIF.DAP j? Í,

INDUSTRIAL consecutive times on each redrawn grid to be considered in conjunction with said pattern masks, where W (fl, f2) is a measurement of co-channel interference between frequency resources fl and f2, in where f (Il; a) is the frequency resource of the sequence of time and frequency resources II for a time slot a and f (12; a) is the frequency resource of the sequence of time and frequency resources II for the time slot a. To guarantee that the pattern masks of said second plurality have the same level of orthogonality to each other, said pattern masks are defined such that, for any sequences Im and Ik that represent respective pattern masks of said second plurality, the following is fulfilled. following relation:

\ 0F &lt;jm, lk) \ &lt;D where D at a predefined threshold. Therefore, intra-super-band interference between pattern masks that can be used concurrently by adjacent cells is reduced.

According to a particular characteristic, an orthogonality factor OF is defined between pairs of sequences of time and frequency resources within multiple frequency superbands i, j over said v consecutive time slots, as follows:

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'NOUSTMIAL

OF (r! .R2) = maxíj (W (fí0'l, l) - {j (P2, l)) + W (fí (r2, l) -fj (r 1,1))) + .. + maxjj (W (fi (r 1, v) - ^ (r2, v)) + W (fí (rXvFrin 1, v)) t&gt; -en where I'l and I'2 are sequences of time resources and frequency defined by two respective pattern masks within several frequency superbands formed over a number of v consecutive time slots in each redrawn grid to be considered in conjunction with said pattern masks, where W (fl, f2) is a measurement of the co-channel interference between the frequency resources fl and f2, where fi (I'l; a) is the frequency resource of the sequence of time and frequency resources I'l for a timeslot a in the super-frequency band i, where fi (I'2; a) is the frequency resource of the sequence of time and frequency resources I'2 for the timeslot heard in the super- frequency band i, where fj (I'l; a) is the frequency resource of the sequence of time and frequency resources I'l for the time slot a in the super frequency band j, and where fj (I'2; a) is the frequency resource of the sequence of time and frequency resources I'2 for timeslot a. To guarantee that the pattern masks of said second plurality have the same level of orthogonality to each other, said pattern masks are defined in such a way that, for any I'm and

I'k representing respective pattern masks of bliss

<img file="MX358486B_D0008.tif" />

second plurality, the following relation is fulfilled:

\ 0F (rm, ¡'k) \ &lt;D where D is a predefined threshold. Therefore, intra-and inter-superband interference between pattern masks that can be used concurrently by adjacent cells is reduced.

According to a particular characteristic, for each time slot of the initial grid, the frequency or frequency bands of the initial grid are distributed uniformly or almost uniformly in terms of quantity between said super-frequency bands.

Therefore, the ability to avoid interference is the same for all time slots.

According to a particular characteristic, the initial grid covers frequencies from 2400 MHz to 2480 MHz, a first frequency super-band groups frequencies from 2400 MHz to 2425 MHz, a second frequency super-band groups frequencies from 2425 MHz to 2450 MHz, and a third frequency super-band groups frequencies of

2450 MHz to 2480 MHz.

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<td>devices</td><td>more</td><td>popul</td><td colspan="2">ares who perform in the band</td><td>ISM</td>

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limited signaling overhead.

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<img file="MX358486B_D0010.tif" />

According to a character p? τ ~ ι - j &lt;-ni_{to κ} _ The grid that was redrawn is such that the time and frequency resource groups are formed complying with the following restriction:

í = i! 2wi ° 8₂(Se¡) 1 = B «t = l where:

- Γ represents the roof operator;

- n represents a number of groups formed from the initial grid;

- Ni represents a number of time slots of the initial grid present in a group identified by an index i;

- Nt represents a number of time slots of the initial grid;

- SBi represents a number of frequency superbands for each of the time slots in the group identified by the index i; Y

- Bt represents a target amount of signaling bits available to indicate, according to the grid that was redrawn, which time and frequency resources are allocated to said transmissions.

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INSTITUTO MEXICANO DE LA EMOEIEDAD IN »UST« AL

Therefore, the redrawn grid can be defined for a target signaling overload.

According to a particular characteristic, the assignments according to the redrawn grid representation are considered by sets of a predefined number of time slots and are associated with respective signal words in a codebook, and the signaling information comprises the code in the codebook that is associated with the time and frequency resources that have been allocated by the first communication device in accordance with the grid representation that was redrawn.

Therefore, the amount of data needed to report the allocated time and frequency resources

<td>agree</td><td>with the grid that</td><td>turned</td><td>to trace</td><td>it is</td>

<td>limited.</td><td></td><td></td><td></td><td></td>

<td>The</td><td>present invention</td><td>I also know</td><td>It refers to</td><td>a</td>

<td>system for</td><td>determine resources</td><td>of time and</td><td>frequency</td><td>from</td>

<td colspan="3">between time resources and frequency of</td><td>a network</td><td>from</td>

wireless communications that are going to be used to carry out transmissions in said wireless communications network, the transmissions are intended to be carried out through resources of time and frequency of

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<img file="MX358486B_D0012.tif" />

the wireless communication network according to an initial grid representation. The system is such that a first device in charge of allocating time and frequency resources comprises: means for obtaining groups of time and frequency resources from the wireless communication network to form a redrawn grid representation; means for allocating time and frequency resources in accordance with the redrawn grid representation and in accordance with a frequency hopping criterion; and means for providing signaling information representative of the time and frequency resources that have been allocated in accordance with the redrawn grid representation obtained. The system is also such that, to determine which time and frequency resources of the initial grid are going to be used to carry out said transmissions, a second device comprises: means for obtaining the signaling information provided by the first device to determine the resources of time and frequency that have been assigned according to the grid representation that was redrawn; and means for applying a predetermined pattern mask over the determined time and frequency resources that have been allocated in accordance with the redrawn grid representation, the pattern mask being such that only

<img file="MX358486B_D0013.tif" />

Initial grid time and frequency is effectively assigned by time slot in each assigned grid time and frequency resource that was redrawn.

Since the characteristics related to the system are similar to those already mentioned with reference to the corresponding aforementioned method, the corresponding advantages are not repeated here.

BRIEF DESCRIPTION OF THE FIGURES

The characteristics of the invention will emerge more clearly from a reading of the following description of an example of the embodiment, said description being produced with reference to the accompanying Figures, among which:

Figure 1 schematically represents a wireless communication network in which the present invention can be implemented;

Figure 2 schematically represents a communication device of the wireless communication network;

Figure 3 schematically represents an algorithm to determine time and frequency resources that will be used to carry out transmissions within the wireless communications network, according to

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<img file="MX358486B_D0014.tif" />

a first embodiment of the present invention?

Figure 4 schematically represents an algorithm for determining time and frequency resources that are to be used to carry out transmissions within the wireless communication network according to a second embodiment of the present invention;

Figure 5 schematically represents an algorithm to determine a redrawn grid of the time and frequency resources that will be used to signal the allocation of time and frequency resources that will be used to carry out the transmissions within the wireless communications network;

Figure 6 schematically represents an algorithm to determine a pattern that will be used to determine, based on the signaling information, the allocation of time and frequency resources that will be used to carry out transmissions within the network of wireless communications;

Figure 7 schematically represents an algorithm to determine a redrawn grid of time and frequency resources and will be used to signal the allocation of time and frequency resources that will be used to carry out transmissions within of the communications network

INSTITUTO MiXICANt, DE IA FROFIEDAU

INDUÍTRIAt

<img file="MX358486B_D0015.tif" />

wireless, as well as a pattern that will be used to determine, from the signaling information, the allocation of time and frequency resources that will be used to carry out the transmissions within the wireless communications network;

Figure 8A schematically represents a

<td>initial grid resources</td><td>from</td><td>weather</td><td>and frequency,</td><td>on</td><td>which</td>

<td>the grid is based that</td><td>I know</td><td>went back</td><td>to draw from</td><td colspan="2">resources of</td>

<td>time and frequency;</td><td></td><td></td><td></td><td></td><td></td>

<td>The figures</td><td>8B</td><td>and 8C</td><td>represent</td><td>from</td><td>way</td>

<td>schematic a first</td><td colspan="2">modality</td><td colspan="2">from the grid</td><td>That</td>

<td colspan="2">redrawn resource</td><td colspan="3">of time and frequency;</td><td></td>

<td>The figures</td><td>8D</td><td>and 8E</td><td>represent</td><td>from</td><td>way</td>

<td>schematic a second</td><td colspan="2">modality</td><td colspan="2">from the grid</td><td>That</td>

<td colspan="2">redrawn resource</td><td colspan="3">of time and frequency;</td><td></td>

<td>The figures</td><td>8F</td><td>and 8G</td><td>represent</td><td>from</td><td>way</td>

<td>schematic a third</td><td colspan="2">modality</td><td colspan="2">from the grid</td><td>That</td>

redrawn of time and frequency resources; Y

Figures 9A, 9B and 9C schematically represent an example of the allocation and signaling of time and frequency resources in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In order to reduce the amount of signaling information required to inform signaling devices

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INDUSTRIAL communication on the resources of it, empr, and frornonpia assigned to carry out transmissions within a wireless communications network, it is proposed to form groups of time and frequency resources to build a grid that was redrawn of time and frequency resources from of an initial grid of time and frequency resources in which time and frequency resources are considered separately. By grouping time and frequency resources and by mapping considering the redrawn grid rather than the initial grid, the amount of signaling information is reduced. To avoid using more time and frequency resources than is actually necessary, a pattern mask is applied in the time and frequency resource allocation stipulated by the signaling information. The pattern mask allows reverting to the initial grid of time and frequency resources, while the signaling information only refers to the redrawn grid of time and frequency resources, which is inherently less accurate than the grid. initial resource time and frequency.

Figure 1 schematically represents a wireless communication network in which the present invention can be implemented.

IMPI

<img file="MX358486B_D0016.tif" />

The wireless communication network shown in Figure 1 comprises a server 100, several access points APs and several mobile terminals. Two APs 110, III are shown illustratively and two mobile terminals 120, 121 are also shown illustratively.

In Figure 1, the mobile terminal 120 communicates within the wireless communications network through the AP 110 and the mobile terminal 121 communicates within the wireless communications network through the AP III, as represented by the arrows. solid line in Figure 1. From the point of view of the mobile terminal 121, downlink communications from the AP

110 to the mobile terminal 120 can interfere with the downlink communications from the AP III to the mobile terminal 121. From the point of view of the mobile terminal 120, the downlink communications from the AP III to the mobile terminal 121 can interfere. with downlink communications from AP 110 to mobile terminal 120. Such interference is represented in Figure 1 by the dashed arrows. Other interference can be generated by other interference factors located in the vicinity of the mobile terminals and / or in the vicinity of the APs.

You can deal with such interference thanks

<img file="MX358486B_D0017.tif" />

Mexican Institute

W LA DEEP1, industrial to frequency hopping when time and frequency are assigned for transmissions. Frequency hopping provides diversity in terms of frequency usage, which allows transmissions to be resistant to narrow band interference.

The server 100 is in charge of making the time and frequency resource allocations within the wireless communication network. To accomplish this, server 100 communicates with APs 110, III to receive and process assignment requests, and to provide information regarding time and frequency resources assigned by server 100 in response to assignment requests to perform transmissions. . The

APs are in charge of providing signaling information representative of said time and frequency resources assigned by the server 100 to any mobile terminal present in an area, also known as a cell, covered by said APs.

In a variant, the time and frequency resource allocations are not made by a server to which the APs are connected, but by the APs themselves.

The time and frequency resources that can be used to carry out transmissions between the AP 110 and the mobile terminal 120 and the transmissions between the AP III

<img file="MX358486B_D0018.tif" />

IMPI

INSTITUTO MIXICANO DB LA FROHEDAD INDUSTRIAL and the mobile terminal 121 can be represented using a so-called initial grid of time and frequency resources. In Figure 8A, an illustrative representation of such an initial grid of time and frequency resources is shown.

In Figure 8A, frequency resources are represented as ordinate (vertical axis) and time resources are represented as abscissa (horizontal axis).

Illustratively, the frequency band from 2400 MHz to

2480 MHz is divided into sixteen time and frequency resources of 5 HMz each. In other words, each arrow on the grid shown in Figure 8A represents a 5 MHz wide frequency resource. Illustratively, time is divided into time slots of 4 ms each. A time frame of twenty time slots is represented by the grid shown in Figure 8A. Each time slot is considered as a time resource. In other words, each column in the grid shown in Figure 8A represents a 4 ms wide time resource. Each frame represented in the grid of Figure 8A then corresponds to a time and frequency resource of 5 MHz over 4 ms.

The transmissions should be made using time and frequency resources of said initial grids.

IMPI

<img file="MX358486B_D0019.tif" />

components

As already mentioned, the éJédllüTóri '&lt;36 Ta¹Signaling according to the initial grid shown in Figure 8A would need at least eighty bits: four bits per time slot to indicate which frequency resource is allocated, considering that a frequency resource has to be allocated for each time slot of the frame time slot considered twenty time slots. Using a redrawn grid formed by the grouping of time and frequency resources from the initial grid and a pattern mask to revert to the initial grid allows the amount of bits needed to perform the signaling to be reduced, as detailed in hereafter.

Figure 2 schematically represents a communication device of the wireless communication network. Said communication device may be a representation of an AP, such as AP 110 and / or it may be a representation of a mobile terminal, such as mobile terminal 120, and / or it may be a representation of server 100.

According to the architecture shown, the communication device comprises the following interconnected by communications 210: a processor, a microprocessor bus, microcontroller or CPU (Central Processing Unit)

<img file="MX358486B_D0020.tif" />

200; a RAM (Random Access Memory) 201, ^ a (Read Only Memory) 202; a HDD (Hard Disk Drive) or an SD (Secure Digital) 203 card reader, or any other device adapted to read information stored on storage media; at least one communication interface 204.

Communication interface 204 allows the communication device to communicate with at least one other communication device on the wireless communication network.

The CPU 200 has the ability to perform instructions loaded into RAM 201 from ROM 202 or from external memory, such as an SD card. After the communication device has been turned on, the CPU

200 has the ability to read instructions from RAM

201 and carry out these instructions. The instructions form a computer program that causes the CPU 200 to perform some or all of the steps in the algorithms described hereinafter.

Any and all of the steps of the algorithms described hereinafter can be implemented in software by executing a set of instructions or program through a programmable computing machine, such as a PC (personal computer), a DSP (data processor). digital signal), or a microcontroller; o í Jl

<img file="MX358486B_D0021.tif" />

4 it can also be implemented in hardware-- through— · through · -¹machine or a dedicated component, such as a FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

Figure 3 schematically represents an algorithm for determining time and frequency resources that are going to be used to carry out transmissions within the wireless communication network, according to a first embodiment of the present invention.

The algorithm of Figure 3 consists of two parts S320 and S330. The first part S320 refers to a process for allocating time and frequency resources to carry out transmissions within the wireless communication network. The first part S320 can be performed by an AP or by the server 100. The second part S330 refers to a process for determining, from the signaling information, which time and frequency resources have been effectively allocated to perform the transmission. The second part S330 can be performed by an AP or by the server 100. Under general considerations, the first part S320 is performed by a first communication device in charge of assigning time and frequency resources to enable transmissions within the wireless communication network and the second part S330 is

<img file="MX358486B_D0022.tif" />

USTlTUTf 'MEXICAN M IA OWNED

INDUSTRIAL performed by a second communication device that wishes to determine the time and frequency resources effectively allocated to allow such transmissions within the wireless communication network.

In the algorithm of Figure 3, the first part

S320 is composed of a sequence of steps S301 to S303, and the second part S330 is composed of a sequence of steps S310 to S313.

In step S301, the first communication device obtains a redrawn grid of time and frequency resources. The redrawn frequency is obtained by grouping time and frequency resources from the initial grid. It is considered within the scope of the algorithm of Figure 3 that the first communication device is based on a static definition of the grid that was redrawn. The grid that is then redrawn is determined in advance and its definition is provided in advance within the wireless communication network, for example, at the installation or initialization of the wireless communication network. The redrawn grid definition can also be stored in a memory of each communication device in the wireless communication network during the manufacturing process and then be

<img file="MX358486B_D0023.tif" />

can recover through the dispnqitivn Hp ρη '”! ??.?:; ·· once it is turned on. In a variant, as detailed hereinafter with reference to Figure 4, the first communication device is based on a dynamic definition of the grid that was redrawn.

In other words, the first communication device obtains groups of time and frequency resources from the wireless communication network to form a grid representation that was redrawn. Time and frequency resource allocations made according to the then redrawn grid require fewer signaling bits compared to time and frequency resource allocations made according to the initial grid, because a fewer time and frequency resources on the redrawn grid compared to the initial grid due to cluster formation.

The redrawn grid can be formed by grouping, identically for consecutive time slots of the starting grid, adjacent frequencies or frequency bands of the starting grid into frequency superbands.

Considering the initial grid of time and frequency resources shown in Figure 8A, in the

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<img file="MX358486B_D0024.tif" />

Figures 8B and 8C show a first axis ™ pi ^ Hp said grid that was redrawn from time and frequency resources. The redrawn grating shown in Figures 8B and 8C is such that, for each time slot of the initial grid, the frequency or frequency bands (frequency resource) of the initial grid are almost uniformly distributed over terms of quantity between said super-frequency bands. The frequency or frequency bands (frequency resources) of the initial grid may be evenly distributed in terms of quantity between said super-frequency bands, as illustrated in Figure 9A.

In Figure 8B, the redrawn grid of time and frequency resources shown in Figure 8A is such that the frequency resources are grouped to form three frequency bands 811, 812 and

813. Frequency bands 811, 812, and 813 are separated from each other in Figure 8B by dashed lines. The 811 frequency band covers six frequency resources of the initial grid shown in Figure 8A, specifically the six 5 MHz wide frequency resources ranging from 2450 MHz to 2480 MHz. The 812 frequency band covers five frequency resources of the initial grid shown in Figure 8A, specifically the five 5 MHz wide frequency resources ranging from 2425 MHz.

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INDUSTRIAL iJCS »¹ at 2450 MHz. The frequency band 812 cuj ^ s.

frequency of the initial grid shown in Figure 8A, specifically the five 5 MHz wide frequency resources ranging from 2400 MHz to 2425 MHz. In the redrawn grid shown in Figures 8B and 8C, there is no time resource groups have been formed; only frequency resource groups have been formed. In Figure 8C, the time and frequency resource groups that have been formed to create the grid that was redrawn from the initial grid are shown. Frequency bands 811, 812, and 813 appear differently in the redrawn grating representation of the

Figure 8C. For each time slot of the considered time frame, three allocations of time and frequency resources can then be made according to the grid that was redrawn, that is, one allocation for each frequency band 811, 812, 813. In comparison, sixteen assignments per time slot can be made according to the initial grid shown in Figure 8A.

Therefore, based on the redrawn grating representation shown in Figure 8C, two flag bits are needed to indicate, for each time slot, which frequency resource is allocated.

Two signaling bits also make it possible to indicate that there is no

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MWICANO INSTITUTE

OF THE YDUSTMAL PROPERTY

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a frequency resource assigned for the rafTUId ds — trtenipu considered (a value to indicate that there is no frequency resource assigned for the time slot

<td>considered,</td><td>a</td><td>value</td><td>in order to</td><td>indicate</td><td>that</td><td>band</td><td>from</td>

<td>frequency</td><td> 811</td><td colspan="2">is assigned</td><td>for the</td><td>groove</td><td colspan="2">of time</td>

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<td colspan="3">significantly less</td><td>what</td><td>at least</td><td colspan="2">eighty bits</td><td>from</td>

signage needed when based on the initial grid.

The groups formed to create the redrawn grid shown in Figure 8C from the initial grid shown in Figure 8A are particularly convenient as each frequency band 811, 812, 813 respectively corresponds to one of the main channel used. in Wi-Fi systems (registered trademark). Frequency band 811 further corresponds to the frequency band that can be impacted by microwave oven operations. Therefore, the interference that results from the communications of Wi-Fi devices (registered trademark) and the interference

<img file="MX358486B_D0026.tif" />

resulting from the operations of hnrnns Hp mirmnnHa ^ can easily be handled by frequency hopping.

Considering the initial grid of time and frequency resources shown in Figure 8A, a second example of a redrawn grid of time and frequency resources is shown in Figures 8D and 8E.

In Figure 8D, the redrawn grid of time and frequency resources shown in Figure 8A is such that the frequency resources are grouped to form three frequency bands 821, 822 and

823 over the first twelve time slots in sequence in the twenty time slot considered time frame. The three frequency bands 821, 822 and 823 respectively correspond to the three frequency bands 811, 812, 813 of the redrawn grid shown in Figures 8B and 8C. For the remaining eight time slots of the twenty time slot considered time frame, all frequency resources are grouped into a frequency band 824.

In the redrawn grid shown in Figures 8D and 8E, the time resource groups have not been formed; only frequency resource groups have been formed. Figure 8E shows the time and frequency resource groups that have been formed to create the grid that was redrawn from the

IMPI

INSTITUTO MUKANU M LA FROFItOAii • NDUSTXIAL

<img file="MX358486B_D0027.tif" />

initial grid. Frequency bands 821, 822, 823, and 824 appear differently in the redrawn grating representation of Figure 8E. For each time slot among the first twelve time slots in sequence in the considered time frame of twenty time slots, three allocations of time and frequency resources can then be made according to the grid that was redrawn, that is i.e. one assignment for each frequency band 821, 822, 823. For each time slot among the remaining eight time slots of the considered time frame of twenty time slots, a single allocation can then be made according to the grid that was redrawn, that is, an allocation for the band of frequency 824. Here again, for comparison, sixteen assignments per time slot can be made according to the initial grid shown in Figure 8A.

Thus, based on the redrawn grating representation shown in Figure 8E, two signaling bits are needed to indicate, for each time slot between the first twelve sequential time slots in the time frame considered from twenty time slots, which frequency resource is assigned. Two signaling bits also allow you to indicate that there is no frequency resource assigned for the slot

INSTITUTO MBKICANO D! THE PROPERTY

INDUSTRIAL time considered. (A value to indicate that there is no frequency resource assigned for the timeslot

<td>considered,</td><td>a</td><td>value for</td><td>indicate</td><td>what</td><td>the</td><td>Band of</td>

<td>frequency</td><td> 821</td><td>is assigned</td><td>for the</td><td colspan="2">groove</td><td>of time</td>

<td>considered,</td><td>a</td><td>value for</td><td>indicate</td><td>what</td><td>the</td><td>Band of</td>

<td>frequency</td><td> 822</td><td>is assigned</td><td>for the</td><td colspan="2">groove</td><td>of time</td>

<td>considered</td><td colspan="2">and a value for</td><td>indicate</td><td>what</td><td>the</td><td>Band of</td>

<td>frequency</td><td> 823</td><td>is assigned</td><td>for the</td><td colspan="2">groove</td><td>of time</td>

<td>considered)</td><td colspan="4">. For the eight time slots</td><td colspan="2">remaining of</td>

time frame considered, a signaling bit is needed to indicate, for each time slot, whether the frequency resource corresponding to frequency band 824 is allocated. This results in a total number of thirty-two signaling bits, which is significantly less than at least eighty signaling bits required when based on the initial grid. Furthermore, signaling information that is thirty-two bits long is conveniently aligned with most of the memory width of computer systems.

Considering the initial grid of time and frequency resources shown in Figure 8A, a third example of a redrawn grid of time and frequency resources is shown in Figures 8F and 8G.

In grid 8F, the grid that was turned

<img file="MX358486B_D0028.tif" />

IMPI

INSTITUTO MIXtCANO PK LA MPHKDAO plot of time and frequency resources moS ^ Mfad ©

Figure 8A is such that the resources Γ ^ 11 ^^ = - 11: i - ^gori grouped to form four frequency bands 831, 832,

833 and 834, for the first twelve time slots in sequence in the considered time frame of twenty time slots. Frequency bands 831, 832, 833 and

834 they are separated from each other in Figure 8F by dashed lines. Frequency band 831 covers four frequency resources of the initial grid shown in Figure 8A, specifically the four 5 MHz wide frequency resources ranging from 2460 MHz to 2480 MHz. Frequency band 832 covers four frequency resources of the initial grid shown in Figure 8A, specifically the four five MHz wide frequency resources ranging from 2440 MHz to 2460 MHz. The 832 frequency band covers four frequency resources of the initial grid shown in Figure 8A, specifically the four five MHz wide frequency resources ranging from 2420 MHz to

2440 MHz. The 834 frequency band covers the four initial grid frequency resources shown in Figure 8A, specifically the four 5 MHz wide frequency resources ranging from 2400 MHz to 2420 MHz. In the redrawn grid shown in Figures 8B and 8C, no time resource pools have been formed; only resource groups have been formed

<img file="MX358486B_D0029.tif" />

frequency. For the eight time slots in the considered time frame of 20 time slots, the frequency resources are grouped to form two frequency bands 835 and 836. The frequency band 835 covers eight frequency resources of the initial grid shown. in Figure 8A, specifically the eight 5 MHz wide frequency resources ranging from 2440 MHz to 2480 MHz.

The 836 frequency band covers eight frequency resources of the initial grid shown in Figure 8A, specifically the eight 5 MHZ wide frequency resources ranging from 2400 MHz to 2440 MHz. In Figure 8G, the resource groups are shown. of time and frequency that have been shaped to create the grid that was redrawn from the initial grid. Frequency bands 831, 832, 833, 834, 835, and 836 appear differently in the redrawn grating representation of Figure 8G. For each time slot among the first twelve time slots in sequence in the considered time frame of 20 time slots, then four allocations of time and frequency resources can be made according to the grid that was redrawn, that is that is, one allocation for each frequency band 831, 832, 833, 834. For each time slot among the remaining eight time slots of the considered time frame of twenty time slots,

IMPI

<img file="MX358486B_D0030.tif" />

then two assignments can be made d ..... mn the grid that was redrawn, that is, one assignment for each frequency band 835, 836. Here again, for comparison, sixteen assignments can be made per time slot according to the initial grid shown in Figure 8A.

Therefore, based on the redrawn grating representation shown in Figure 8G, two signaling bits are needed to indicate, for each time slot between the first twelve sequential time slots in the time frame considered from twenty time slots, which frequency resource is assigned. In this case, it is considered that a frequency resource is assigned for each of the time slots of the considered time frame. For the remaining eight time slots of the considered time frame, a flag bit is needed to indicate, for each time slot, which frequency resource among the frequency bands 835, 836 is allocated. A total number of 32 signaling bits results, which is significantly less than at least the eighty signaling bits required when based on the initial grid. Also, signaling information that is 32 bits long is conveniently aligned with the memory width of most communication systems.

<img file="MX358486B_D0031.tif" />

computer.

The redrawn grid of time and frequency resources can take on various other forms. Although Figures 8B to 8G show clusters formed along the initial grid frequency resource axis, clusters may be formed along the time resource axis. Clusters can also be formed along both the frequency resource axis and the time resource axis.

In a more general approach, the groups formed to create the redrawn grid meet the following constraint:

^ / V_¿ = W_t ^ rN, log₂(SB,) l = B, where:

- represents the roof operator;

- n represents a number of groups formed from the initial grid;

- Ni represents a number of time slots (time resources) of the initial grid present in a group identified by an index i;

- Nt represents an amount of time slots

IMPI

<img file="MX358486B_D0032.tif" />

(time resources) of the initial grid ^. pq φρό r. __A7_t= 20 according to the initial grid shown in Figure 8A;

- SBi represents a number of frequency superbands for each of the time slots (time resource) in the group identified by the index i; Y

- Bt represents a target amount of signaling bits available to indicate, according to the grid that was redrawn, which time and frequency resources are allocated to said transmissions.

The above description, and more particularly the illustrative examples of the signaling information are based on a signaling per time slot, that is, an amount of N (N&gt; 0) signaling bits is provided to indicate, for each slot time, which frequency resource has been allocated in said time slot by the first communication device. In another embodiment, all the assignments of the twenty time slots are fully signaled using a mapping between all the assignment possibilities (3²⁰ allocation possibilities when defining three frequency superbands over the twenty time slots) and signal words of predefined length, eg thirty-two bits. Said mapping can be represented in a code book. To reduce the size

<img file="MX358486B_D0033.tif" />

from the codebook, assignments can be eiBwgielG'gnl · ·¹By sets of a predefined number of time slots, for example, five time slots are considered together. A signal word is then assigned to each possible assignment of the predefined number of time slots. Therefore, when considering the redrawn grid shown in Figure 8C and when considering signal words representative of assignments of five timeslots together, there are 3⁵ allocation possibilities (three frequency super-bands are defined over the twenty time slots in Figure 8C), which can be represented by signal words of length equal to eight bits. Finally, the signaling for the twenty assignments requires four set assignments of five time slots. This results in a total amount of 32 signaling bits, which is significantly less than at least eight signaling bits required when based on the initial grid. Furthermore, signaling information that is thirty-two bits long is conveniently aligned with the memory width of most computer systems.

Returning again to Figure 3, in the next step S302, the first communication device

<img file="MX358486B_D0034.tif" />

DI LA PROPERTY INDUSTRIAL allocates time and frequency resources according to the redrawn grid representation obtained, to allow such transmissions. In other words, the first communication device performs mapping based on the redrawn grid representation obtained. Therefore, a time and frequency resource that has been grouped with at least other time and frequency resources to form the obtained redrawn grid representation cannot be independently assigned. Resource allocation time and frequency is performed according to a criterion of frequency hopping to provide frequency diversity and robustness to interference to such transmissions and, therefore, improve performance, ie, the probability suc to of such transmissions.

In the next step S303, the first communication device provides signaling information within the wireless communication network. For example, when the first communication device is the

AP 110, AP 110 transmits said signaling information to mobile terminal 120 to enable mobile terminal 120 to determine which time and frequency resources have been allocated to said transmissions. In this case, these transmissions are

<img file="MX358486B_D0035.tif" />

downlink transmissions from "-i" jf — AP — Η-Θ— mobile terminal 120 and for which the mobile terminal 120 needs to know which time and frequency resources are used by the AP 110 to perform said downlink transmissions, and / or said transmissions are uplink transmissions from the mobile terminal

120 to the AP 110 and for which the mobile terminal 120 needs to know which time and frequency resources are going to be used by the mobile terminal 120 to perform said uplink transmissions.

The signaling information is at least representative of the time and frequency resources that have been allocated, according to the redrawn grid obtained from the time and frequency resources, in order to allow such transmissions.

In the next step S310, the second communication device receives the signaling information transmitted by the first device in the step S303.

In the next step S311, the second communication device obtains, from the received signaling information, the time and frequency resources, which have been allocated in step S302 according to the grid that was redrawn.

In the next step S312, the second communication device applies a predetermined pattern mask on the time and frequency resources

<img file="MX358486B_D0036.tif" />

have been assigned in accordance with the representative

<img file="MX358486B_D0037.tif" />

grid that was redrawn. The application of the predetermined pattern mask allows the second communication device to determine which time and frequency resources of the initial grid have to be used effectively to make said transmissions, although the signaling information only refers to the grid that was redrawn. When applied to a group of time and frequency resources of the redrawn grid, the default pattern mask allows the second communication device to determine which time and frequency resources of that group have to be used effectively. to make such transmissions. The pattern mask is such that only one time and frequency resource of the initial grid is effectively allocated per time slot in each allocated time and frequency resource of the redrawn grid. This ensures that, after applying the pattern mask on the allocated time and frequency resources according to the grid that was redrawn, only one time and frequency resource from the initial grid is allocated per time slot.

It is considered in the scope of the algorithm of the

IMPI

<img file="MX358486B_D0038.tif" />

Figure 3 that the second communication device is based

.................. . . ..

in a static direction of the pattern mask. The pattern mask is then determined in advance and its definition is provided in advance within the wireless communication network, for example, at the setup or initialization of the wireless communication network.

The definition of the pattern mask can also be stored in a memory of each communication device of the wireless communication network during the manufacturing process and then retrieved by the communication device once it is turned on. In a variant, as detailed hereinafter with reference to Figure 4, the second communication device is based on a dynamic definition of the pattern mask.

In the next step S313, the time and frequency resources identified in step S312, according to the initial grid representation, are used to perform said transmissions. For example, when the second communication device is mobile terminal 120, mobile terminal 120 uses the time and frequency resources identified in step

S312 to receive data through downlink communications from the AP 110 and / or to transmit data through uplink communications to the AP

110.

<img file="MX358486B_D0039.tif" />

Mexican ustituto OE LA PDOPISDAD.

INDUSTRIAL ***.

Consider an illustrative performance result of the algorithm of Figure 3, as shown in Figures 9A to 9C. Figure 9A depicts a grid that was redrawn as obtained by executing step S301. Considering the initial grid shown in Figure 8A, the time and frequency resources are grouped to form four frequency bands. The groups are then formed on a time slot basis. Each group then consists of four time and frequency resources from the initial grid.

In Figure 9A, the black rectangles represent the time and frequency resources that have been allocated for said transmissions in step S302. The white rectangles represent the time and frequency resources that have not been allocated for said transmissions in step S302. The signaling information provided by the first communication device in step S303 is then representative of the black rectangles shown in Figure 9A.

Figure 9B represents a pattern mask that can be used to determine which initial grid time and frequency resources have to be used to perform said transmissions. The pattern mask is represented on the initial grid of time and frequency resources. For considerations of

IMPI

MEXICAN INSTITUTE

O £ LA FXePIFUAU INtXJÍTXJAL

<img file="MX358486B_D0040.tif" />

Clearly, the frequency bands that allowed the groups of the redrawn grid to form are shown by the dashed lines, although the definition of these frequency bands is beyond the scope of the pattern mask. The black boxes represented in Figure 9B correspond to the time and frequency resources that can be used to carry out transmissions, while the white boxes correspond to the time and frequency resources that cannot be used to carry out transmissions.

It can be seen that, when the pattern mask of Figure 9B and the redrawn grid of Figure 9A are superimposed, only one resource of the initial grid is marked by a black box in each group of the grid that is redrawn. This ensures that, after masking the allocated time and frequency resources according to the grid that was redrawn, only one resource from the initial grid is allocated per time slot.

Figure 9C represents the time and frequency resources of the initial grid, which have to be used to carry out said transmissions. The black boxes represented in Figure 9C correspond to the time and frequency resources that will be used to carry out the transmissions, while the boxes

INrrrTUTO MUtICANU of nepiíDAD • noustwai ν ^ * ΏΓ · »5 targets correspond to the time and frequency resources that will not be used to carry out transmissions. The time and frequency resources that are to be used to carry out the transmissions are then obtained by superimposing the grids shown in Figures 9A and 9B. The time and frequency resources assigned according to the redrawn grid (black rectangles in Figure 9A) are the only ones that are considered; then, within said time and frequency resources assigned according to the redrawn grid, only the time and frequency resources marked in the pattern mask (black boxes in Figure 9B) are considered as the time and frequency resources to be used to carry out the transmissions.

Figure 4 schematically represents an algorithm for determining time and frequency resources that will be used to carry out transmissions within the wireless communication network, according to a second embodiment of the present invention. The difference between the algorithm of Figure 4 and the algorithm of Figure 3 is that, in the algorithm of Figure 4, the redrawn grid and / or the pattern mask are dynamically selected.

The algorithm in Figure 4 consists of two

6

<img file="MX358486B_D0041.tif" />

IMPI

ΙΝΓΓΙΤυΤΟ MEXICANO ME LA RHONELiAU INOUSTMAL parts S420 and S430. The first part S420 refers to a process for allocating time and frequency resources to perform transmissions within the wireless communication network. The first part S420 can be performed by an AP or by the server 100. The second part S430 relates to a process for determining, from the signaling information, which time and frequency resources have been effectively allocated to perform the transmission. The second part S430 can be performed by an AP or by the server 100. Under general considerations, the first part S420 is carried out by a first communication device in charge of allocations of time and frequency resources to allow transmissions within the wireless communication network and the second part S430 is carried out by a second communication device You want to determine the time and frequency resources effectively allocated to allow such transmissions within the wireless communications network.

In the algorithm of Figure 4, the first part S420 is composed of a sequence of steps S401 to S403, and the second part S430 is composed of a sequence of steps S410 to S414.

In step S401, the first communication device selects a grid that was redrawn

7

ΙΜΡΙ

<img file="MX358486B_D0042.tif" />

from a set of redrawn grids of predefined resources of time and frequency. The predefined redrawn grids are obtained by grouping time and frequency resources of the initial grid, as already described with reference to Figure 3. The dynamic selection of the redrawn grid is described hereinafter in a particular embodiment with reference to Figure 5.

In the next step S402, the first communication device selects a pattern mask from a set of predefined pattern masks. The dynamic selection of the pattern mask is described hereinafter in a particular embodiment with reference to Figure 6.

Respective dynamic selections of the redrawn grid and the pattern mask can be made together. Joint dynamic selections of the redrawn grid and the pattern mask are described hereinafter in a particular embodiment with reference to Figure 7.

Furthermore, although Figure 4 depicts dynamic selections of the redrawn grid and pattern mask, only the redrawn grid or pattern mask can be dynamically selected by the first communication device.

<img file="MX358486B_D0043.tif" />

<img file="MX358486B_D0044.tif" />

In the next step S403, the first communication -tiiopooitive fc-rw-i allocates time and frequency resources according to the grid that was redrawn selected, in order to allow said transmissions. In other words, the first communication device performs allocation based on the redrawn grid selected. The allocation of time and frequency resources is carried out according to a frequency hopping criterion to provide frequency diversity to said transmissions.

Because the redrawn grid is based on the initial grid where groups of time and frequency resources have been formed, this means that fewer signaling bits are required to inform the second communication device about the time resources. and frequency assigned.

In the next step S404, the first communication device provides signaling information within the wireless communication network. For example, when the first communication device is the AP 110, the AP 110 transmits said signaling information to the mobile terminal 120 to allow the mobile terminal 120 to determine which time and frequency resources have been allocated to said transmissions. In this case, these transmissions are link transmissions.

<img file="MX358486B_D0045.tif" />

downstream from AP 110 to terminal TTtióví 1 120 and for which the mobile terminal needs to know which time and frequency resources are used by AP 110 to carry out said downlink transmissions, and / or said transmissions are uplink transmissions from mobile terminal 120 to AP 110 and for which mobile terminal 120 needs to know which time and frequency resources are going to be used by mobile terminal 120 to perform said uplink transmissions. .

The signaling information is at least representative of the time and frequency resources that have been allocated, according to the redrawn grid obtained from the time and frequency resources to allow such transmissions. When the redrawn grid has been dynamically selected by the first communication device, the flagging information is further representative of the selected redrawn grid. When the pattern mask has been dynamically selected by the first communication device, the signaling information is further representative of said selected pattern mask.

In the next step S410, the second communication device receives the signaling information

ΙΜΡΙ

<img file="MX358486B_D0046.tif" />

transmitted by the first device in step E4U3.

In the next step S411, the second communication device obtains, from the received signaling information, the time and frequency resources that have been allocated in step S302 according to the grid that was redrawn.

In the next step S412, the second communication device obtains, from the received signaling information, information representative of the pattern mask to be applied to determine which time and frequency resources of the initial grid have to be used. to make such transmissions.

In the next step S413, the second communication device applies the obtained pattern mask on the determined time and frequency resources that have been allocated according to the grid representation that was redrawn.

In the same way as for the algorithm of Figure 3, the application of the pattern mask obtained allows the second communication device to determine which time and frequency resources of the initial grid representation have to be used effectively to perform said transmissions, although the signaling information only refers to

ΙΜΡΪ

<img file="MX358486B_D0047.tif" />

to the grid representation that is νο1νΤϊ? · ϋΐ · ΤΐΛΛΗΓΐ

In one embodiment, when the first communication device selects the pattern mask from a set of predefined pattern masks, said pattern masks have the same level of orthogonality to each other. Such an arrangement is particularly useful when the server 100 selects the AP profit pattern masks. In this case, the server 100 can guarantee that the time and frequency resources used in adjacent cells are orthogonal or observe the same level of interference with each other.

To achieve this, an orthogonality factor OF can be defined as a co-channel interference function (the channel being the frequency spectrum in which the frequency hopping mechanism described here applies, for example, for example, the frequency band ISM) depending on a frequency distance between two frequency resources. When defining pattern masks, one goal is to equalize the orthogonality factor OFE between said pattern masks. It is recalled that the pattern masks are such that only one time and frequency resource of the initial grid is effectively allocated per time slot in each assigned time and frequency resource of the redrawn grid.

<img file="MX358486B_D0048.tif" />

<img file="MX358486B_D0049.tif" />

In a first modality, assume that ~~ WTT^,T'f 2) a measurement of co-channel interference between frequency resources fl and f2. Assume that II and 12 are sequences of time and frequency resources defined by two masks

<td>pattern</td><td>respective</td><td>within</td><td>from</td><td>bliss</td><td>super-band</td><td>from</td>

<td>frequency</td><td>identically</td><td>formed</td><td colspan="2">over one</td><td>amount of</td><td>V</td>

<td>slots</td><td colspan="2">consecutive times</td><td>on</td><td>each</td><td>grid that</td><td>I know</td>

redrawn to be considered in conjunction with those pattern masks. II corresponds to a first sequence of time and frequency resources [f (Il, l), f (Il, v)] and 12 corresponds to a second sequence of time and frequency resources [f (I2, l), f ( I2, v)] according to a first example, when considering the redrawn grating shown in Figure 8C, three frequency superbands are defined over the twenty time slots of the considered time frame. The orthogonality factor OF can then be calculated between pairs of time and frequency resource sequences within each super-frequency band in said twenty time slots (v = 20). According to a second example, when considering the redrawn grid shown in Figure 8E, three frequency superbands are defined over the first twelve time slots in sequence of the considered time frame and a super frequency is defined. -frequency band over the last eight time slots in

ΙΜΡΙ

<img file="MX358486B_D0050.tif" />

sequence of the considered time frame. The orthogonality factor OF can be calculated between pairs of sequences of time and frequency resources within each super-frequency band over said first twelve time slots in sequence of the considered time frame. A first part of the pattern masks can then be defined for said twelve first time slots in sequence of the considered time frame (v = 12). The orthogonality factor OF can then be calculated between pairs of time and frequency resource sequences within each super-frequency band over the last eight sequential time slots of the considered time frame. A second part of the pattern masks can then be defined for the last eight sequential time slots of the considered time frame (v = 8).

The orthogonality factor OF is defined as follows:

OF (11,12) - W (f (11,1) -f (I2,1)) + W (f (I2,1) -f (11,1)) + ...

+ W (f (Il; v) -f (12; v)) + W (f (I2; v) -f (I1; v))

Then, a set of pattern masks is selected such that, for any sequences Im and lk that represent respective pattern masks from that set, the following relationship holds:

IMPI

<img file="MX358486B_D0051.tif" />

where D is a predefined threshold.

Therefore, the robustness for intra-super-band interference between each pair of II and 12 sequences leading to the selected pattern masks is improved.

In a second embodiment, when several frequency superbands are defined by the grating that was redrawn for at least one time slot, intra- and inter-super-band interference can exist between two pattern masks. The second modality focuses on improving said intra- and inter-super-band interference.

Assume that W (fl-f2) is a measurement of co-channel interference between time and frequency resources fl and f2.

Assume that I'l is a sequence of time and frequency resources defined by a first pattern mask within said first super-band of frequency i identically formed over a number of v consecutive time slots on the redrawn grid. to be considered in conjunction with said pattern mask and within a second super-band of frequency j identically formed over said v consecutive time slots in said grating that was redrawn. It should be noted that, when f j, the inter-super-band interference is considered; and when i = j, intra-super-band interference is considered. Assume I'2 is a

IMPI time and frequency defined by

<img file="MX358486B_D0052.tif" />

pattern within said first and within said second super-sequence of resources of a second super-band frequency mask frequency band over said v consecutive time slots in said grid that was redrawn. I'l corresponds to a first sequence of time and frequency resources [fi (I'l; l), fj (1'1; 1), fi (I '1; v), fj (I'l / vj] and

I'2 corresponds to a second sequence of time and frequency resources [fi (I'2; l), fj (I '2; 1), ..., fi (I'2; v), fj (I' 2, · v)]. The orthogonality factor OF can be calculated between pairs of sequences of time and frequency resources within several super-frequency bands over said v consecutive time slots.

The orthogonality factor OP is defined as follows:

OF (ri, I'2) = maxij (W (fi (I'l, l) -e (r2, l)) + W (fi (r2, l) -S (ri, I))) + .. .

+ max_isj(W (fi (I'l, v) -fj (r2, v)) + W (fi (I'2, v) -fj (ri, v)))

Then, a set of pattern masks is selected such that, for any I'm and I'k sequences that have n respective pattern masks from that set, the following relationship holds:

&lt;D

Therefore, the robustness for inter-super-band and intra-super-band interference between each pair of I'l and I'2 sequences leading to the masks is improved.

<img file="MX358486B_D0053.tif" />

IMPI ~ of selected pattern.

Figure 5 schematically represents an algorithm to determine a redrawn grid of time and frequency resources that will be used for signaling allocation of time and frequency resources that will be used to perform said transmission within the wireless communications network.

In a step S501, the first communication device selects a redrawn grid from a set of predefined redrawn grids obtained by pooling time and frequency resources from the initial time and frequency resource grid .

In a next step S502, the first communication device calculates a first figure of merit representative of the robustness to interference for the selected redrawn grid. The figures of merit are quantities, being the result for an application of a predefined function, said quantities are used to characterize the performance of sequences of time and frequency resources that can be assigned to carry out said transmissions.

For example, when knowledge about the Signal-to-Interference Ratio becomes available more

ΙΜΡΪ

MSWCANO INSTITUTE OF INDUSTRIAL PROPERTY

<img file="MX358486B_D0054.tif" />

Noise (SINR) for the first communication device.

For each time slot and frequency resource, the first communication device can calculate a performance metric that must be maximized, such as channel capacity. Therefore, by combining the grid that was redrawn selected and the pattern mask to be applied by the second communication device (said pattern mask being fixed in the scope of the algorithm in Figure 5), a rate of data

<td>average</td><td>equivalent to</td><td>can achieve</td><td>can be</td>

<td>calculated</td><td>for n transmissions</td><td>Thanks to the</td><td>following</td>

<td>expression</td><td>mathematics:</td><td></td><td></td>

<td></td><td>n X ^ log₂(l + SINR (k) ·) k = 0</td><td></td><td></td>

<td></td><td>where SINR (k) is the</td><td colspan="2">SINR expected in the k-th</td>

The time and frequency resource selected according to the grid that was redrawn and the selected pattern mask.

In a next step S503, the first communication device checks whether at least one other grid that was redrawn from among the set of predefined redrawled grids has yet to be processed. When at least that other grid that was redrawn still has to be processed, step S501 is repeated selecting that other grid that was redrawn; otherwise, step S504 is performed.

<img file="MX358486B_D0055.tif" />

In step S504, the priman Ηίορηςίτίππ.

OF INDUSTRIAL PROPERTY

<img file="MX358486B_D0056.tif" />

Communication selects the grid to be redrawn from the set of predefined redrawn grids showing the best first figure of merit. The selected redrawn grid is then used by the first communication device to perform time and frequency resource allocation and further provide the corresponding signaling information. Because the algorithm of Figure 5 allows the first communication device to dynamically select the appropriate redrawn grid, the signaling information provided by the first communication device should be representative of the selected redraw grid. out of the set of predefined redrawn grids. For example, when the cardinality of the set of predefined redrawn grids is equal to 4, two flag bits can be used to indicate which of the redrawn grid sets of predefined redrawn grids has been. selected by the first communication device, when the second communication device has a priori knowledge of the set of predefined redrawn grids. Said signaling bits can then be an index of the

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redrawn grid among the set of predefined redrawn grids. Such signaling bits do not need to be transferred every time signaling information has to be provided. The redrawn grid can be selected and used for several successive assignments of time and frequency resources.

Figure 6 schematically represents an algorithm to determine a pattern mask that will be used to determine, from the signaling information, the allocation of time and frequency resources that will be used to carry out said transmissions within the wireless communications network.

In a step S601, the first communication device selects a pattern mask from a set of predefined pattern masks.

In a next step S602, the first communication device calculates a second figure of merit representative of the robustness to interference for the selected pattern mask.

For example, when knowledge of the Signal to Interference plus Noise ratio (SINR) becomes available to the first communication device, for each time slot and frequency resource, the first communication device can calculate a metric of

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throughput to be maximized, r-nme 1 at channel capacity. Therefore, by combining the redrawn grid (said redrawn grid being fixed in the algorithm scope of Figure 6, and the selected pattern mask, an equivalent average data rate can be calculated that can be achieved for n transmissions thanks to the following mathematical expression:

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-¿, Ιο * (1 + SINRÍk »where SINR (k) is the expected SINR at the selected k-th time and frequency resource according to the grid that was redrawn and the selected pattern mask.

In a next step S603, the first communication device checks whether at least one other pattern mask from among the set of predefined pattern masks still has to be processed. When at least that other pattern mask has to be processed, step S601 is repeated selecting that other pattern mask; otherwise, a step S604 is performed.

In step S604, the first communication device selects the pattern mask from the set of predefined pattern masks showing the best second figure of merit. The pattern mask

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The selected one is then used by the second communication device to determine the time and frequency resources of the initial grid representation to be used to perform said transmissions. Because the algorithm of Figure 6 allows the first communication device to dynamically select the appropriate pattern mask, the signaling information provided by the first communication device should be representative of the pattern mask selected from the set of predefined pattern masks, when the second communication device has a priori knowledge of the set of predefined pattern masks. Said signaling bits can then be an index of the pattern mask selected from the set of predefined pattern masks. For example, when the cardinality of the set of predefined pattern masks is equal to 4, two flag bits can be used to indicate which pattern mask among the set of predefined pattern masks has been selected by the first communication device. Such signaling bits do not need to be transferred each time the signaling information has to be provided. The pattern mask can be selected and used for several successive assignments of time and frequency resources.

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Figure 7 represents de ^ a ^ ara c.cqv.c ^^ '¹- nn algorithm to determine a redrawn grid of time and frequency resources that will be used to signal the allocation of time and frequency resources that will be used to perform said transmissions within the wireless communications network, as well as a pattern to be used to determine, from the signaling information, the allocation of time and frequency resources that will be used to carry out said transmissions within the wireless communications network.

In a step S701, the first communication device selects a redrawn grid from a set of predefined redrawn grids obtained by pooling time and frequency resources from the initial time and frequency resource grid. .

In a next step S702, the first communication device selects a pattern mask from a set of predefined pattern masks.

In a next step S703, the first communication device calculates a third figure of merit representative of the robustness to interference for the selected pattern mask and the selected redrawn grid.

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For example, when νηρίνρτί'ί .j_.jr.15l is; first communication device the knowledge about the Signal to Interference plus Noise ratio (SINR), for each time slot and frequency resource, the first communication device can calculate a performance metric that must be maximized, such as channel capacity . Therefore, by combining the selected redrawn grid and the selected pattern mask, an equivalent average data rate can be calculated that can be achieved for n streams using the following mathematical expression:

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-Y log₂(l + SlNR (k »where SINR (k) is the expected SINR at the k-th time and frequency resource selected according to the selected redrawn grid and the selected pattern mask.

In a next step S704, the first communication device checks whether at least one other pattern mask from among the set of predefined pattern masks has to be processed. When at least that other pattern mask has to be processed, step S702 is repeated

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Communication checks if at least one other grid that was redrawn out of the set of predefined redrawn grids has to be processed. When at least that other grid that was redrawn has to be processed, step S701 is repeated selecting that other grid that was redrawn; otherwise, a step S706 is performed.

In step S706, the first communication device selects the pattern mask from the set of predefined pattern masks and the grid that was redrawn from the set of predefined redrawn grids that together show the best third. figure of merit. The selected redrawn grid is then used by the first communication device to perform allocation of time and frequency resources and further to provide the corresponding signaling information. The selected pattern mask is then used by the second communication device to determine the time and frequency resources of the initial grid representation to be used to perform said transmissions. Because the algorithm in Figure 7 allows the first communication device to dynamically select the appropriate pattern mask and redrawn grid, the

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IIOUST1UAL signaling information provided by the first communication device should be representative of the pattern mask selected from the set of predefined pattern masks as well as the redrawn grid selected from the set of redrawn grids. plot predefined, when the second communication device has a priori knowledge of the set of predefined redrawn grids and of the set of predefined pattern masks. Said flag bits may then be an index of the selected redrawn grid from the set of predefined redrawn grids and an index of the selected pattern mask from the set of predefined pattern masks. For example, when the cardinality of the set of predefined pattern masks equals four and when the cardinality of the set of predefined redrawn grids equals four, Four flag bits can be used to indicate which pattern mask among the set of predefined pattern masks has been selected by the first communication device and which grid that was redrawn from the set of redrawn grids predefined has been selected by the first communication device. In a variant, said bits

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Signaling then can be a c-or ^^ gc -rio codebook that lists all possible combinations of said redrawn grid and said pattern mask. Such signaling bits do not need to be transferred every time signaling information has to be provided. The pattern mask and the redrawn grid can be selected and used for several successive assignments of time and frequency resources.