Pilot pattern design for small size resource block in OFDMA systems
First Claim
1. A method comprising:
- a) defining a resource block by a wireless communication device in an Orthogonal Frequency Division Multiple Access (OFDMA) communications system, wherein the resource block is a two-dimensional block having a first number of frequency tones along frequency domain and a second number of time slots along time domain;
b) determining a specified number of pilot tones to be allocated within the resource block by the device based on a set of communications system requirements, wherein the resource block is partitioned into a number of sub-blocks based on the resource block size and the specified number; and
c) positioning the specified number of a plurality of pilot tones by the device in each sub-block such that average distance between the allocated pilot tones and data tones is minimized in each sub-block and that pilot-to-pilot spacing in the resource block is substantially maximized by allocating the pilot tones in different time slots or in different frequency tones, wherein the specified number is equal to m, wherein the resource block is partitioned into n equal sub-blocks, wherein m is a multiple of n, and wherein the positioning in c) involves allocating m/n pilots in each of the partitioned sub-blocks such that average pilot-to-data distance is minimized, wherein m and n are positive integers.
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Abstract
In OFDMA wireless communications systems, pilot pattern design is optimized based on predefined resource block size. The number of pilots and the spacing between pilots within a resource block is determined based on a set of system requirements. In one novel aspect, if resource block size is smaller than three in either frequency or time domain, then the pilots are allocated such that average pilot-to-data distance is minimized and that pilot-to-pilot distance is as large as possible. In one example, m pilots are allocated in an i×j resource block. The resource block is partitioned into n equal sub blocks, where m is a multiple of n. Within each sub block, m/n pilots are positioned such that average pilot-to-data distance is minimized. On the other hand, if resource block size is larger than or equal to three in both frequency and time domain, then pilots are allocated to avoid channel extrapolation.
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Citations
18 Claims
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1. A method comprising:
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a) defining a resource block by a wireless communication device in an Orthogonal Frequency Division Multiple Access (OFDMA) communications system, wherein the resource block is a two-dimensional block having a first number of frequency tones along frequency domain and a second number of time slots along time domain; b) determining a specified number of pilot tones to be allocated within the resource block by the device based on a set of communications system requirements, wherein the resource block is partitioned into a number of sub-blocks based on the resource block size and the specified number; and c) positioning the specified number of a plurality of pilot tones by the device in each sub-block such that average distance between the allocated pilot tones and data tones is minimized in each sub-block and that pilot-to-pilot spacing in the resource block is substantially maximized by allocating the pilot tones in different time slots or in different frequency tones, wherein the specified number is equal to m, wherein the resource block is partitioned into n equal sub-blocks, wherein m is a multiple of n, and wherein the positioning in c) involves allocating m/n pilots in each of the partitioned sub-blocks such that average pilot-to-data distance is minimized, wherein m and n are positive integers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A wireless communications device, comprising:
a transmitter that transmits a plurality of pilot tones for a data stream using a two-dimensional resource block having a first number of frequency tones along frequency domain and a second number of time slots along time domain; and
a pilot allocation module that allocates a specified number of the plurality of pilot tones, wherein the specified number is determined based on a set of communications system requirements, wherein the resource block is partitioned into a number of sub-blocks based on the specified number, wherein the specified number of pilot tones is allocated in each sub-block such that average distance between the allocated pilot tones and data tones is minimized in each sub-block and that pilot-to-pilot spacing in the resource block is substantially maximized by allocating the pilot tones in different time slots or in different frequency tones, wherein the specified number is equal to m, wherein the resource block is partitioned into n equal sub-blocks, wherein m is a multiple of n, and wherein m/n pilot tones are allocated in each of the partitioned sub-blocks such that average pilot-to-data distance is minimized, wherein m and n are positive integers.- View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus, comprising:
- an antenna; and
means for transmitting via the antenna a plurality of pilot tones located within a two-dimensional resource block having a first number of frequency tones along frequency domain and a second number of time slots along time domain, wherein a specified number of pilot tones are determined based on a set of communications system requirements, wherein the resource block is partitioned into a number of sub-blocks based on the specified number, wherein the specified number of the plurality of pilot tones is allocated in each sub-block such that average distance between the allocated pilot tones and data tones is minimized in each sub-block and that pilot-to-pilot spacing in the resource block is substantially maximized by allocating the pilot tones in different time slots or in different frequency tones, wherein the specified number is equal to m, wherein the resource block is partitioned into n equal sub-blocks, wherein m is a multiple of n, and wherein m/n pilot tones are allocated in each of the partitioned sub-blocks such that average pilot-to-data distance is minimized, wherein m and n are positive integers. - View Dependent Claims (16, 17, 18)
- an antenna; and
Specification