# US 2013/0155985 A1 · Method for communicating in mobile system

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- Number: US 2013/0155985 A1
- Document ID: US20130155985A1
- Status: Published application
- Kind: A1
- Application number: 13/766,850
- Filed: 2013-02-14
- Published: 2013-06-20
- Earliest claimed: 2008-03-26
- Assignees: Koninklijke Philips Electronics N.V.
- Inventors: Boris Skoric; Ludovicus M. G. M. Tolhuizen; Matthew P.J. Baker
- Web page: https://patentgrep.com/patent/US20130155985A1

## CPC

- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04W 72/20: Control channels or signalling for resource management
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

The present invention relates to a method for communicating from a primary station to a plurality of secondary station, comprising the step of at the primary station allocating a resource to the secondary stations over the time on the basis of a hash function, wherein the hash function is such that the probability that two secondary stations are allocated common resources in two subframes substantially equals the product of the probability that the two secondary stations are allocated a common resource in the first subframe and the probability that the two secondary stations are allocated a common resource in the second subframe.

## Claims

### Claim 1

A method for communicating between a primary station and a plurality of secondary stations, comprising the steps:
(a) configuring each secondary station to search at least one of a plurality of search spaces, each search space comprising at least one resource set, where at least one resource set might be used to transmit a message to the considered secondary station,
(b) determining the search space of a given secondary station on the basis of a hash function fs(x) wherein x∈X, s∈{0, 1, . . . , T−1} into {0, 1, . . . , M−1}, wherein x corresponds to a parameter of the secondary station, and s corresponds to a subframe number, and X is the range of the hash, and T indicates a quantity of hash functions, and M is a number in a series of numbers that are all different from each other, and wherein the hash function has the following properties:
for each s∈{0, 1, . . . , T−1} the function fs attains each element in {0, 1, . . . , M−1} approximately equally often; and
for all distinct s,t in {0, 1, . . . , T−1}, where t is a different subframe than s, the number of elements x in X is such that fs(x)=i and ft(x)=j is approximately the same for all values of i and j; and
(c) at each secondary station, searching in the configured at least one search space for a control message from the primary station addressed to the considered secondary station, and receiving the control message.

### Claim 2 (depends on 1)

The method of claim 1, wherein the hash function results in a substantially uniform probability of configuring each of the available resources to a given secondary station in a given subframe.

### Claim 3 (depends on 1)

The method of claim 1, wherein for two distinct subframes, s and t, the outputs of the hash functions are substantially independent from each other.

### Claim 4 (depends on 1)

The method of claim 1, wherein the parameter of the secondary station is an identifier of the secondary station.

### Claim 5 (depends on 1)

The method of claim 1, wherein the hash function has the form:
f(x,s)=(h(x)mod g(s))mod M,
where x is a parameter of each secondary station, s is the subframe number, h is a function dependent on x, g is a function dependent on s, M is a constant, and mod is the modulo function.

### Claim 6 (depends on 4)

The method of claim 4, wherein h is a constant multiplier.

### Claim 7 (depends on 4)

The method of claim 4, wherein the parameter of the secondaly station is an identifier of the secondary station.

### Claim 8 (depends on 4)

The method of claim 4, wherein for each value of s, g(s)is a prime number.

### Claim 9

A primary station comprising means for communicating with a plurality of secondary stations, the primary station further comprising:
allocating means to allocate at least one resource set to a given secondary station into at least one of a plurality of search spaces, each search space comprising at least one resource set, wherein the search space of the given secondary station is determined on the basis of a hash function fs(x); wherein x∈X, s∈{0, 1, . . . , T−1} into {0, 1, . . . , M−1}, wherein x corresponds to a parameter of the secondary station, and s corresponds to a subframe number, and X is the range of the hash, and T indicates a quantity of hash functions, and M is a number in a series of numbers that are all different from each other, and wherein the hash function has the following properties:
for each s∈{0, 1, . . . , T−1}, the function fs attains each element in {0, 1, . . . , M−1} approximately equally often;
for all distinct s,t in {0, 1, . . . , T−1}, where t is a different subfrarne than s, the number of elements x in X is such that fs(x)=i and ft(x)=j is approximately the same for all values of i and j.

### Claim 10

A secondary station comprising means for communicatinz with a primary station, the secondary station further comprising
control means configured to search at least one of a plurality of search spaces, each search space comprising at least one resource set, where at least one resource set might be used to transmit a message to the considered secondary station, wherein the search space of the secondary station is determined on the basis of a hash function fs(x) wherein x∈X, s∈{0, 1, . . . , T−1} into {0, 1, . . . , M−1}, whereon x corresponds to a parameter of the secondary station, and s corresponds to a subframe number, and X is the range of the hash, and T indicates a quantity of hash functions, and M is a number in a series of numbers that are all different from each other, and wherein the hash function has the following properties:
for each s∈{0, 1, . . . , T−1}, the function fs attains each element in {0, 1, . . . , M−1} approximately equally often;
for all distinct s,t in {0, 1, . . . . , T−1} where t is a different subframe than s, the number of elements x in X is such that fs(x)=i and ft(x)=j is approximately the same for all values of i and j; and
wherein the control means are configured formearching in the configured at least one search space for a control message from the primary station addressed to the considered secondary station, and receiving the control message.