Delivery Server, and Terminal Device

1. A delivery server in a content delivery system, wherein the content delivery system uses a multi-hop communication technology to deliver content from the delivery server via a radio communication network to multiple terminal devices, wherein the multiple terminal devices are located downstream from the delivery server on the radio communication network and connected in multiple stages, wherein each of the multiple terminal devices comprises a storage configured to store the delivered content, and wherein the multiple terminal devices include: a first terminal device configured to receive the content from upstream in the radio communication network and store the received content in the storage device of the first terminal device; and a second terminal device located one hop downstream from the first terminal device in the radio communication network, wherein the delivery server is configured to: instruct the first terminal device to deliver the content stored in the storage of the first terminal device to the second terminal device; and manage a status of delivery of the content, based on information that is reported from the first terminal device and indicates a result of delivery of the content from the first terminal device to the second terminal device.

2. The delivery server according to claim 1 , wherein when the delivery of the content from the first terminal device to the second terminal device is interrupted, the first terminal device reports, to the delivery server, the information indicating a delivery interruption and an interruption location in the content, and wherein the delivery server is further configured to: search for a new communication path to the second terminal device, in response to the information indicating the delivery interruption, and instruct a third terminal device of the multiple terminal devices, which is located one hop upstream from the second terminal device on the new communication path, to deliver, to the second terminal device, a remaining part of the content following the interruption location and stored in the storage of the third terminal device.

3. The delivery server according to claim 1 , wherein when the delivery of the content from the first terminal device to the second terminal device is interrupted, the first terminal device reports, to the delivery server, the information indicating a delivery interruption and an interruption location in the content, and wherein the delivery server is further configured to: hold an alternative communication path to the second terminal device; and instruct, in response to the information indicating the delivery interruption, a third terminal device of the multiple terminal devices, which is located one hop upstream from the second terminal device on the alternative communication path, to deliver, to the second terminal device, a remaining part of the content following the interruption location and stored in the storage of the third terminal device.

4. The delivery server according to claim 1 , wherein the delivery server is further configured to create radio connection relations between the delivery server and the multiple terminal devices and between the multiple terminal devices, by using at least one of a positional relation between the delivery server and the multiple terminal devices and a radio communication environment relation between the delivery server and the multiple terminal devices.

5. The delivery server according to claim 4 , wherein the delivery server is further configured to use at least one of the positional relation and the radio communication environment relation to instruct two or more terminal devices of the multiple terminal devices to concurrently deliver the content stored in the respective storages of the two or more terminal devices.

6. The delivery server according to claim 1 , wherein the delivery server is further configured to give priority to such a terminal device of the multiple terminal devices that is located upstream from another terminal device in the radio communication network, in regard to an order of delivering the content.

7. The delivery server according to claim 1 , wherein the delivery server and each of the multiple terminal devices are configured to deliver the content by multicasting communication.

8. The delivery server according to claim 7 , wherein the delivery server is further configured to perform delivery confirmation of the content after delivering the content to fourth terminal devices of the multiple terminal devices by the multicasting communication, and wherein if some content is missing in any of the fourth terminal devices, the delivery server is further configured to redeliver the missing content to the any fourth terminal device.

9. The delivery server according to claim 7 , wherein the delivery server is further configured to perform delivery confirmation of the content after delivering the content to fourth terminal devices of the multiple terminal devices by the multicasting communication, and wherein if there is no response from any of the fourth terminal device, the delivery server is further configured to: search for a new communication path to the any fourth terminal device; and instruct a fifth terminal device of the multiple terminal devices, which is located one hop upstream from the any fourth terminal device on the new communication path, to deliver, by the multicasting communication, the content stored in the storage of the fifth terminal device to the any fourth terminal device.

10. The delivery server according to claim 7 , wherein the first terminal device performs delivery confirmation of the content after delivering the content to the second terminal device by the multicasting communication, wherein if the first terminal device reports, to the delivery server, the information indicating that there is no response from the second terminal device, the delivery server is further configured to: search for a new communication path to the second terminal device; and instruct a third terminal device of the multiple terminal devices, which is located one hop upstream from the second terminal device on the new communication path, to deliver, by the multicasting communication; the content stored in the storage of the third terminal device to the second terminal device.

11. A terminal device in a content delivery system, wherein the content delivery system uses a multi-hop communication technology- to deliver content from a delivery server via a radio communication network to multiple terminal devices, wherein the multiple terminal devices are located downstream from the delivery server on the radio communication network and connected in multiple stages, wherein each of the multiple terminal devices comprises a storage configured to store the delivered content, and wherein the multiple terminal devices include: a first terminal device; as the terminal device, configured to receive the content from upstream in the radio communication network and store the received content in the storage device of the first terminal device; and a second terminal device located one hop downstream from the first terminal device in the radio communication network, wherein the terminal device as the first terminal device is further configured to: receive a first instruction from the delivery server, the first instruction instructing the terminal device to deliver the content stored in the storage of the terminal device to the second terminal device; deliver, in response to the first instruction; the content stored in the storage of the terminal device to the second terminal device; and report, to the delivery server, information indicating a result of delivery of the content from the terminal device to the second terminal device.

12. The terminal device according to claim 11 , wherein if the delivery of the content from the terminal device to the second terminal device is interrupted, the terminal device is further configured to report, to the delivery server, the information indicating a delivery interruption and an interruption location in the content, wherein the delivery server searches for a new communication path to the second terminal device, in response to the information indicating the delivery interruption, wherein the delivery server instructs a third terminal device of the multiple terminal devices, which is located one hop upstream from the second terminal device on the new communication path, to deliver, to the second terminal device, a remaining part of the content following the interruption location and stored in the storage of the third terminal device, and wherein the third terminal device is configured to deliver, to the second terminal device, the remaining part of the content following the interruption location and stored in the storage of the third terminal device.

13. The terminal device according to claim 11 , wherein if the delivery of the content from the terminal device to the second terminal device is interrupted, the terminal device is further configured to report, to the delivery server, the information indicating a delivery interruption and an interruption location in the content, wherein the delivery server holds an alternative communication path to the second terminal device, wherein the delivery server instructs, in response to the information indicating the delivery interruption, a third terminal device of the multiple terminal devices, which is located one hop upstream from the second terminal device on the alternative communication path, to deliver, to the second terminal device, a remaining part of the content following the interruption location and stored in the storage of the third terminal device, and wherein the third terminal device is configured to deliver, to the second terminal device, the remaining part of the content following the interruption location and stored in the storage of the third terminal device.

14. The terminal device according to claim 11 , wherein the first terminal device requires a first content including the content, the second terminal device requires a second content including the content, and the terminal device is further configured to store the first content and the second content in the storage.

15. The terminal device according to claim 11 , wherein the delivery server and each of the multiple terminal devices are configured to deliver the content by multicasting communication.

16. The terminal device according to claim 15 , wherein the terminal device is further configured to perform delivery confirmation of the content after delivering the content to the second terminal device by the multicasting communication; and wherein if some content is missing in the second terminal device, the terminal device is further configured to redeliver the missing content to the second terminal device.

17. The terminal device according to claim 15 , wherein the terminal device is further configured to perform delivery confirmation of the content after delivering the content to the second terminal device by the multicasting communication, wherein if there is no response from the second terminal device, the terminal device is further configured to report, to the delivery server, the information indicating that there is no response from the second terminal device, wherein the delivery server searches for a new communication path to the second terminal device, wherein the delivery server instructs a third terminal device of the multiple terminal devices, which is located one hop upstream from the second terminal device on the new communication path, to deliver, by the multicasting communication, the content stored in the storage of the third terminal device to the second terminal device, and wherein the third terminal device is configured to deliver, by the multicasting communication, the content stored in the storage of the third terminal device to the second terminal device.